# Project Management — AMR ROS2 K4

> **Project**: Blockly ROS2 Robot Controller (Kiwi Wheel AMR)
> **ROS2 Distro**: Jazzy
> **Last Updated**: 2026-03-18
> **Current Focus**: Task #6 — HMI Interactive Widgets

Dokumentasi lengkap dapat dilihat di [DOCUMENTATION.md](DOCUMENTATION.md).

# Aturan pengggunaan dokumen

bab pada dokumen merepresentasikan alur rencana pengembangan. 
## Potential Enhancements

bab ini digunakan untuk Feasibility Study

## Planned Feature

Backlog. Setelah kita pelajari untuk di kerjakan maka kita pindah ke backlog

## Feature Task

penjabaran Pekerjaan yang ready untuk dikerjakan. Task harus dijelaskan apa yang akan dikerjakan dan terdapat definition of done nya
Berikut ini adalah template untuk pembuatan task :

```

## <nomor task> <judul task> : <state: [ ] >
jelaskan permasalah di bab ini
### Bug 1 [ ] : Keterangan bug untuk rekap permasalahan
**Symtomp**    : jelaskan masalahnya!
**Root Couse** : masalah ini dikarenakan apa?
**Fix**        : bagaimana cara fix nya?
### Definition Of Done
[ ] DoD 1
[ ] DoD 2
[ ] Bug 1 ... 

```

---

# Potential Enhancements
this list is short by priority
- **Feasibility Study to implement Controller**: mobile robot need controller to move flawlesly.
- **Launch files**: ROS2 launch files to start all nodes with one command includ node in raspberry pi
- **Simulation**: Integrate with Gazebo/Isaac Sim for testing Kiwi Wheel kinematics before deploying to hardware
- **Block categories**: Future blocks grouped into Robot, Sensors, Navigation categories

# Feature Task

## 3 Enhancement: PCA9685 — 16-Channel PWM Controller (I2C) : [ ]
PCA9685 adalah 16-channel, 12-bit PWM controller via I2C. Motor DC kiwi wheel menggunakan 6 channel (3 motor × 2: PWM + direction), sehingga 10 channel tersedia untuk extensi (servo, LED, dll). Node ini general-purpose — mengontrol channel mana saja via Blockly block dengan parameter address, channel, dan PWM value.

### Implementasi

#### A. Package Structure (C++, ament_cmake)
```
src/pca9685_node/
├── CMakeLists.txt              # ament_cmake — NO external lib dependency
├── package.xml                 # depend: rclcpp, blockly_interfaces
├── include/pca9685_node/
│   └── pca9685_node.hpp        # Pca9685Node class + I2C helpers
└── src/
    ├── pca9685_node.cpp         # I2C init, write_callback, set_pwm()
    └── main.cpp                 # rclcpp::spin(node)
```

Hardware interface menggunakan Linux I2C (`/dev/i2c-X`) via `ioctl()` — tidak perlu external library, cukup `linux/i2c-dev.h` (kernel header).

#### B. ROS2 Interface

**New message** — `blockly_interfaces/msg/PwmWrite.msg`:
```
uint8 address       # I2C address (default 0x40, configurable via solder bridges: 0x40–0x7F)
uint8 channel       # PWM channel (0–15)
uint16 value        # Duty cycle (0–4095, 12-bit resolution)
```

**Topic**: `/pwm/write` (executor → pca9685_node)

**ROS2 Parameters** (configurable via `--ros-args -p`):
| Parameter | Type | Default | Fungsi |
|---|---|---|---|
| `i2c_device` | string | `/dev/i2c-1` | Linux I2C device path |
| `frequency` | int | 50 | PWM frequency Hz (semua channel) |

PCA9685 write-only — tidak perlu `PwmRead.msg`.

#### C. Node Behavior — `Pca9685Node`
1. **Constructor**: open `i2c_device`, configure prescaler berdasarkan `frequency` param
2. **Subscribe** `/pwm/write` (`PwmWrite`) — set duty cycle via I2C register write
3. **`set_pwm(address, channel, value)`**: select I2C slave address via `ioctl(I2C_SLAVE)`, write 4 bytes ke channel registers
4. **Multi-address support**: satu node bisa mengontrol multiple PCA9685 boards (address dikirim per-message, `ioctl(I2C_SLAVE)` di-set setiap write)
5. **Cleanup**: close file descriptor di destructor

PCA9685 register map:
| Register | Address | Fungsi |
|---|---|---|
| MODE1 | 0x00 | Sleep/restart, auto-increment |
| LED0_ON_L | 0x06 | Channel 0 ON timing (4 registers per channel) |
| PRE_SCALE | 0xFE | PWM frequency: `prescale = round(25MHz / (4096 × freq)) - 1` |

#### D. Handler — `blockly_executor/handlers/pwm.py`
```python
@handler("pwm_write")
def handle_pwm_write(params, hardware):
    address = int(params["address"], 16)  # hex string → int
    channel = int(params["channel"])
    value = int(params["value"])
    # Dummy: log only. Real: publish PwmWrite to /pwm/write
```
Lazy-create publisher di `hardware.node._pwm_write_pub`, sama dengan pola `gpio.py`.

#### E. Blockly Block — `pwmWrite.js`
```
┌──────────────────────────────────────────────┐
│ PCA9685  addr: [0x40]                        │
│          channel: [0 ▾]    pwm: [■ value]    │
└──────────────────────────────────────────────┘
```
- **addr**: `FieldDropdown` — common addresses (0x40–0x47)
- **channel**: `FieldNumber` (0–15)
- **pwm**: `ValueInput` (0–4095) — accepts expression blocks, uses `String(expr)` pattern
- Category: `Robot`, Command: `pwm_write`

#### F. pixi.toml Changes
- `setup-dep`: tambah `i2c-tools` (optional, untuk debugging `i2cdetect`)
- `build-pca9685`: `colcon build --packages-select pca9685_node` (depends-on: setup-dep, build-interfaces)
- `pca9685-node`: `ros2 run pca9685_node pca9685_node`

Tidak perlu conda deps baru — Linux I2C headers sudah tersedia di kernel.

#### G. Penggunaan

```bash
# Default — /dev/i2c-1, 50 Hz
pixi run pca9685-node

# Ganti I2C device dan frequency via --ros-args
source install/setup.bash
ros2 run pca9685_node pca9685_node --ros-args -p i2c_device:=/dev/i2c-0 -p frequency:=1000

# Cek I2C bus yang tersedia di Pi
ls /dev/i2c-*           # list semua bus
i2cdetect -y 1          # scan device di bus 1 (perlu i2c-tools)
```

**Catatan**: `pixi run pca9685-node` menggunakan parameter default. Untuk override parameter, jalankan `ros2 run` langsung (setelah `source install/setup.bash`) karena pixi task tidak meneruskan `--ros-args` ke proses inner.

### Definition Of Done
- [x] `src/pca9685_node/` berisi `CMakeLists.txt`, `package.xml`, `include/`, `src/`
- [x] `blockly_interfaces/msg/PwmWrite.msg` terdaftar di `rosidl_generate_interfaces()`
- [x] `pixi run build-interfaces` berhasil — PwmWrite.msg ter-generate
- [x] `pixi run build-pca9685` berhasil di Raspberry Pi (native build) tanpa error
- [ ] Node berjalan: `pixi run pca9685-node` — subscribe `/pwm/write`
- [ ] Parameter `i2c_device`, `frequency` berfungsi via `--ros-args -p`
- [x] Handler `pwm_write` berfungsi di dummy mode (test passes)
- [x] Blockly block `pwmWrite` muncul di toolbox, generate valid JS code
- [ ] End-to-end: Blockly block → executor (real) → `/pwm/write` → pca9685_node → I2C write

## 4 Enhancement: AS5600 — 12-bit Magnetic Rotary Encoder (I2C) : [ ]
AS5600 adalah 12-bit magnetic rotary position sensor via I2C. Kiwi wheel AMR menggunakan 3 encoder (satu per roda) untuk feedback posisi. AS5600 memiliki **fixed I2C address (0x36)** — untuk 3 module, setiap encoder menggunakan **I2C bus terpisah** (e.g., `/dev/i2c-1`, `/dev/i2c-3`, `/dev/i2c-4`).

> **Note**: Legacy `EncoderRead.msg`, `encoder.py` handler, dan `encoderRead.js` block telah dihapus dan diganti oleh **Task #5 (Unified Odometry Interface)**. `as5600_node` sekarang hanya publish `nav_msgs/Odometry` ke `odometry_encoder/odom`.

### Implementasi

#### A. Package Structure (C++, ament_cmake)
```
src/as5600_node/
├── CMakeLists.txt              # ament_cmake — depend: rclcpp, nav_msgs, geometry_msgs
├── package.xml
├── include/as5600_node/
│   └── as5600_node.hpp         # As5600Node class + kinematics + I2C helpers
└── src/
    ├── as5600_node.cpp          # I2C read + kiwi wheel kinematics + nav_msgs publish
    └── main.cpp                 # rclcpp::spin(node)
```

Hardware interface menggunakan Linux I2C (`/dev/i2c-X`) via `ioctl()` — tidak perlu external library, cukup `linux/i2c-dev.h` (kernel header).

#### B. ROS2 Interface

Menggunakan **`nav_msgs/Odometry`** (standar ROS2) — lihat Task #5 untuk detail fields dan kinematics.

**Topic**: `odometry_encoder/odom` (as5600_node → executor)

**ROS2 Parameters** (configurable via `--ros-args -p`):
| Parameter | Type | Default | Fungsi |
|---|---|---|---|
| `i2c_devices` | string[] | `["/dev/i2c-1"]` | List of I2C device paths, satu per encoder |
| `publish_rate` | double | 10.0 | Publish frequency Hz |
| `wheel_radius` | double | 5.0 | Radius roda (cm) — HARUS di-tune |
| `wheel_distance` | double | 15.0 | Jarak center-to-wheel (cm) — HARUS di-tune |
| `wheel_angles` | double[] | [0, 2π/3, 4π/3] | Sudut posisi roda (rad) |

#### C. pixi.toml
- `build-as5600`: `colcon build --packages-select as5600_node` (depends-on: setup-dep, build-interfaces)
- `as5600-node`: `ros2 run as5600_node as5600_node`

#### D. Penggunaan

```bash
# Default — /dev/i2c-1, 10 Hz, 1 encoder
pixi run as5600-node

# 3 encoder pada bus terpisah, 20 Hz, custom wheel geometry
source install/setup.bash
ros2 run as5600_node as5600_node --ros-args \
  -p i2c_devices:="['/dev/i2c-1', '/dev/i2c-3', '/dev/i2c-4']" \
  -p publish_rate:=20.0 \
  -p wheel_radius:=5.0 \
  -p wheel_distance:=15.0
```

### Definition Of Done
- [x] `src/as5600_node/` berisi `CMakeLists.txt`, `package.xml`, `include/`, `src/`
- [x] `pixi run build-as5600` berhasil di Raspberry Pi (native build) tanpa error
- [ ] Node berjalan: `pixi run as5600-node` — publish `odometry_encoder/odom`
- [ ] Parameter `i2c_devices`, `publish_rate`, `wheel_radius`, `wheel_distance` berfungsi via `--ros-args -p`
- [ ] End-to-end: as5600_node → `odometry_encoder/odom` → executor cache → Blockly

## 5 Enhancement: Unified Odometry Interface — nav_msgs/Odometry : [ ]
Interface odometry menggunakan standar ROS2 `nav_msgs/Odometry` agar kompatibel dengan ekosistem ROS2. Setiap jenis sensor odometry (encoder, IMU, optical) publish ke topic terpisah `odometry_<type>/odom` menggunakan message type yang sama.

**Motivasi**: Modularitas — tambah sensor baru cukup buat node yang publish `nav_msgs/Odometry` ke `odometry_<type>/odom`. Dari Blockly, user pilih source via dropdown.

**Arsitektur**:
```
as5600_node (encoder)     → odometry_encoder/odom  (nav_msgs/Odometry)
future: imu_node          → odometry_imu/odom      (nav_msgs/Odometry)
future: optical_node      → odometry_optical/odom   (nav_msgs/Odometry)
```

**Satuan**: Mengikuti REP-103 kecuali jarak menggunakan **centimeter (cm)** karena rentang pergerakan robot kecil. Angular menggunakan radian.

**Blocker**: Implementasi sensor baru (IMU, optical) menunggu desain mekanik final.

### Implementasi

#### A. Standard Interface — `nav_msgs/Odometry`
Tidak menggunakan custom message. `nav_msgs/Odometry` sudah tersedia di RoboStack. Message fields yang digunakan:
- `pose.pose.position.x/y` — posisi robot (cm)
- `pose.pose.orientation` — quaternion dari heading (2D: z=sin(θ/2), w=cos(θ/2))
- `twist.twist.linear.x/y` — kecepatan robot (cm/s)
- `twist.twist.angular.z` — kecepatan angular (rad/s)
- `header.frame_id` = `"odom"`, `child_frame_id` = `"base_link"`

#### B. AS5600 Node — Kiwi Wheel Kinematics
`as5600_node` menghitung robot-level odometry langsung dari 3 encoder menggunakan kiwi wheel forward kinematics, publish ke `odometry_encoder/odom` (`nav_msgs/Odometry`).

Legacy `EncoderRead.msg` dan `/encoder/state` topic telah dihapus — clean break, hanya `nav_msgs/Odometry`.

**Kiwi Wheel Forward Kinematics** (3 roda @ 120°):
```
Constraint: ωᵢ = (1/r)(-vx·sin(αᵢ) + vy·cos(αᵢ) + L·ωz)

Forward kinematics (3 roda → robot velocity):
vx  = (r/n) · Σ(-ωᵢ·sin(αᵢ))     [cm/s]
vy  = (r/n) · Σ( ωᵢ·cos(αᵢ))     [cm/s]
ωz  = r/(n·L) · Σ(ωᵢ)            [rad/s]

Pose integration (Euler):
x  += (vx·cos(θ) - vy·sin(θ))·dt   [cm]
y  += (vx·sin(θ) + vy·cos(θ))·dt   [cm]
θ  += ωz·dt                         [rad]
```

#### C. Handler — `odometry.py` (returns JSON)
```python
@handler("odometry_read")
def handle_odometry_read(params, hardware):
    source = params.get("source", "encoder")
    # Returns ALL fields as JSON: {"x":0.0, "y":0.0, "heading":0.0, "vx":0.0, "vy":0.0, "omega_z":0.0}
```
Lazy-create subscriber per source ke `odometry_<source>/odom`. Satu action call return semua data sekaligus — efisien, tidak perlu action call per-field.

#### D. Blockly Blocks — Fetch Once, Extract Many
Dua block terpisah untuk efisiensi (1 action call untuk semua field):

**Block 1: `getOdometry`** (`odometryRead.js`) — Value block, fetch all data:
```
┌─────────────────────────────────┐
│ getOdometry [Encoder ▾]         │ → output: Object
└─────────────────────────────────┘
```
Digunakan dengan Blockly built-in "set variable to" block:
```
set [odom ▾] to [getOdometry [Encoder ▾]]    ← 1 action call
```

**Block 2: `getValueOdometry`** (`odometryGet.js`) — Value block, extract field (no action call):
```
┌───────────────────────────────────────────────┐
│ getValueOdometry [X (cm) ▾] from [odom ▾]     │ → output: Number
└───────────────────────────────────────────────┘
```
Fields: `X (cm)`, `Y (cm)`, `Heading (rad)`, `Vel X (cm/s)`, `Vel Y (cm/s)`, `Angular Vel (rad/s)`

#### E. Future Phases (blocked on mekanik)
- Sensor nodes baru (`imu_node`, `optical_node`) publish `nav_msgs/Odometry` ke `odometry_<type>/odom`
- Update `odometryRead.js` dropdown source untuk sensor baru
- Handler `odometry.py` auto-subscribe ke topic baru via `_SOURCE_TOPICS` dict

### Definition Of Done
- [x] Interface menggunakan `nav_msgs/Odometry` (bukan custom message)
- [x] `as5600_node` publish ke `odometry_encoder/odom` dengan kiwi wheel kinematics
- [x] Legacy `EncoderRead.msg`, `encoder.py`, `encoderRead.js` dihapus — clean break
- [x] Handler `odometry_read` return JSON semua fields (bukan per-field)
- [x] Blockly: `getOdometry` (fetch) + `getValueOdometry` (extract) — 1 action call
- [x] `pixi run build-as5600` berhasil — as5600_node compile dengan nav_msgs dependency
- [x] Handler `odometry_read` berfungsi di dummy mode (test passes)
- [ ] End-to-end: Blockly → executor (real) → cache `odometry_encoder/odom` → return JSON
- [x] Integration test `test_block_odometry.py` passes di dummy mode

## 6 Enhancement: HMI Interactive Widgets — Button, Slider, Switch : [x]
HMI panel sebelumnya hanya memiliki widget **indicator** (satu arah: code → display): LED, Number, Text, Gauge. Enhancement ini menambahkan widget **control** (dua arah: user input ↔ code): Button, Slider, dan Switch — mengikuti konsep LabVIEW "Controls vs Indicators".

Setiap widget control memiliki **SET block** (statement, buat/konfigurasi widget) dan **GET block** (value, baca state interaksi user). Semua client-side JS, tidak ada perubahan Python handler atau ROS2.

### Implementasi

#### A. Block Definitions (6 file baru)
Semua di `src/blockly_app/blockly_app/ui/blockly/blocks/`:

| File | Tipe Block | Deskripsi | Output |
|------|-----------|-----------|--------|
| `hmiSetButton.js` | Statement | `HMI Button [name] label [text] color [dropdown]` | — |
| `hmiSetSlider.js` | Statement | `HMI Slider [name] = [value] min [n] max [n]` | — |
| `hmiSetSwitch.js` | Statement | `HMI Switch [name] state: [boolean]` | — |
| `hmiGetButton.js` | Value | `HMI Button pressed? [name]` | Boolean |
| `hmiGetSlider.js` | Value | `HMI Slider value [name]` | Number |
| `hmiGetSwitch.js` | Value | `HMI Switch state [name]` | Boolean |

#### B. HMI Manager (`hmi-manager.js`)
- 3 render function: `_renderButton`, `_renderSlider`, `_renderSwitch`
- 3 setter: `setButton(name, label, color)`, `setSlider(name, value, min, max)`, `setSwitch(name, state)`
- 3 getter: `getButton(name)`, `getSlider(name)`, `getSwitch(name)`
- Interaktivitas hanya aktif di runtime mode — design mode non-interactive (preview)

#### C. Getter Behavior
- **Button — latch-until-read**: `getButton()` return `true` sekali per klik, lalu auto-reset ke `false`. Mencegah satu klik terbaca berkali-kali di HMI loop 20Hz
- **Slider — `_userValue` tracking**: Memisahkan nilai user-drag dari programmatic `setSlider()`. Mencegah `setSlider()` di loop menimpa posisi drag user
- **Switch — toggle**: `getSwitch()` return boolean state saat ini. User klik untuk toggle ON/OFF

#### D. File yang Dimodifikasi
- `manifest.js` — 6 entry baru
- `hmi-manager.js` — render, setter, getter, serialization, default sizes
- `hmi-preview.js` — design-time preview untuk 3 SET block
- `index.html` — CSS untuk button, slider (range input), switch (toggle track + thumb)

### Bug 1 [x] : UI Freeze pada `while(true)` Loop di Main Program

**Symptom**: Ketika Main Program menggunakan `while(true)` untuk polling `HMI.getButton()`, seluruh UI freeze — HMI panel tidak update, tombol Stop tidak responsif.

**Root Cause**: JavaScript single-threaded. `highlightBlock` override di `_runConcurrent` (debug-engine.js) hanya yield ke **microtask queue** (`await` pada fungsi sinkron → resolved promise). Microtask tidak pernah memberi giliran ke **macrotask queue** dimana click events, `requestAnimationFrame`, dan HMI loop `setTimeout(r, 50)` berada.

```
while(true) → await highlightBlock() → microtask yield → while(true) → ...
                                         ↑ macrotask queue STARVED
                                         (click events, setTimeout, paint — tidak pernah jalan)
```

**Fix**: Tambahkan periodic yield ke macrotask queue (~60Hz) di `highlightBlock` override. Setiap 16ms, `setTimeout(r, 0)` memaksa browser memproses macrotask sebelum resume.

```javascript
var _lastYield = Date.now();
window.highlightBlock = async function (blockId) {
    if (debugState.stopRequested) throw new Error('STOP_EXECUTION');
    originalHighlight(blockId);
    var now = Date.now();
    if (now - _lastYield >= 16) {  // 16ms = ~60fps
        _lastYield = now;
        await new Promise(function (r) { setTimeout(r, 0); });
    }
};
```

Fix diterapkan di:
- `_runConcurrent()` — Run mode concurrent (Main + HMI)
- `_runSingle()` — Run mode single (Main saja, sebelumnya tidak punya override sama sekali)

### Bug 2 [x]: Button tidak cukup cepat untuk menangkap logika dari UI.

**Symptom**: Ketika membuat program `while(getButton()!= true) {delay(500);}` logika button dari HMI tidak tercatat — `getButton()` selalu return `false` meskipun button sudah diklik.

**Root Cause**: HMI loop (~20Hz) memanggil `setButton('Btn1', 'Press', '#2196f3')` setiap ~50ms. Setiap panggilan memicu `_scheduleRender` → `requestAnimationFrame` → `_render()` yang **menghancurkan DOM button lama** (`el.textContent = ''`) dan membuat elemen `<button>` baru.

Event `click` membutuhkan `mousedown` + `mouseup` pada **elemen DOM yang sama**. Karena DOM button diganti setiap ~50ms, jika user menekan button (mousedown) lalu re-render terjadi sebelum mouseup, elemen yang menerima mousedown sudah tidak ada — `click` event tidak pernah fire, `widget._pressed` tetap `false`.

```
t=0ms     : User mousedown pada Button-A (DOM element)
t=16ms    : requestAnimationFrame → _render() → Button-A DIHANCURKAN → Button-B DIBUAT
t=100ms   : User mouseup → tapi Button-A sudah tidak ada!
            → click event TIDAK FIRE
            → widget._pressed tetap false
t=500ms   : getButton('Btn1') → return false  ← bug
```

**Fix**: Ganti event `click` → `pointerdown` di `_renderButton()` (`hmi-manager.js`). `pointerdown` fire **langsung saat ditekan** tanpa menunggu mouseup, sehingga state tersimpan sebelum re-render menghancurkan DOM.

```javascript
// SEBELUM (click — butuh mousedown+mouseup pada elemen yang sama):
btn.addEventListener('click', function () {
    widget._pressed = true;
});

// SESUDAH (pointerdown — fire langsung saat ditekan):
btn.addEventListener('pointerdown', function () {
    widget._pressed = true;
});
```

### Bug 3 [x] : `setSwitch()` menimpa state user toggle setiap 50ms

**Symptom**: Ketika switch state ditampung ke variabel (`led = getSwitch()`) lalu digunakan di `setSwitch('Switch1', Boolean(led))` dalam HMI loop, switch tidak bisa di-toggle — selalu stuck di `false`.

**Root Cause**: HMI loop berjalan ~20Hz (50ms), Main Program polling setiap 500ms. Ketika user toggle switch → `widget.state = true`, dalam 50ms HMI loop memanggil `setSwitch('Switch1', Boolean(led))` dimana `led` masih bernilai lama (`false`) — **menimpa toggle user kembali ke `false`** sebelum Main Program sempat membacanya.

```
t=0ms   : led = undefined → HMI: setSwitch('Switch1', false) → widget.state = false
t=50ms  : User klik switch → widget.state = true ✓
t=55ms  : HMI loop: setSwitch('Switch1', Boolean(led)) → led masih false!
          → widget.state = false ← USER TOGGLE DITIMPA!
t=500ms : Main: led = getSwitch('Switch1') → false (sudah ditimpa)
```

Masalah yang sama dengan Slider yang sudah di-solve menggunakan `_userValue` / `_userInteracting` tracking.

**Fix**: Tambahkan `_userState` tracking — memisahkan state dari user interaction vs programmatic `setSwitch()`. Mengikuti pola yang sama dengan Slider (`_userValue`).

Perubahan di `hmi-manager.js`:
1. `_renderSwitch` — render menggunakan `_userState` jika ada; toggle menyimpan ke `_userState` (bukan `state`); ganti `click` → `pointerdown` (konsisten dengan fix button Bug 2)
2. `setSwitch` — hanya re-render jika user belum interaksi (`_userState === undefined`)
3. `getSwitch` — return `_userState` jika ada, fallback ke `state`
4. `_resetToPreview` — `delete widget._userState` saat kembali ke design mode

### Bug 4 [x] : `setSlider()` menimpa posisi drag user setelah release

**Symptom**: Slider stuck di angka 0 — tidak bisa di-drag. HMI loop memanggil `HMI.setSlider('Slider1', Number(slide), 0, 100)` dimana `slide` awalnya 0, dan setiap kali user drag lalu release, slider kembali ke 0.

**Root Cause**: `_userInteracting` flag hanya `true` **selama drag aktif** (mousedown→mouseup). Begitu user release slider, `_userInteracting = false`, dan dalam 50ms HMI loop memanggil `setSlider()` yang menimpa `_userValue` kembali ke nilai `slide` lama (0) — sebelum Main Program sempat membaca via `getSlider()`.

```
t=0ms   : User drag slider ke 50 → _userInteracting=true, _userValue=50
t=100ms : User release → _userInteracting=false
t=105ms : HMI loop: setSlider('Slider1', Number(slide), 0, 100)
          → _userInteracting is false → _userValue = 0 ← DITIMPA!
t=500ms : Main: slide = getSlider('Slider1') → 0 (sudah ditimpa)
```

Masalah identik dengan Switch (Bug 3) — `_userInteracting` hanya protect selama interaksi aktif, bukan setelahnya.

**Fix**: Tambahkan `_userHasInteracted` flag yang **persist** setelah release. Sekali user pernah drag slider, `setSlider()` tidak akan overwrite `_userValue` lagi.

Perubahan di `hmi-manager.js`:
1. `_renderSlider` — set `_userHasInteracted = true` pada `input` event (saat user drag)
2. `setSlider` — skip `_userValue` overwrite dan `_scheduleRender` jika `_userHasInteracted` true
3. `_resetToPreview` — reset `_userHasInteracted = false` saat kembali ke design mode

### Definition Of Done
- [x] 6 block file dibuat (SET + GET untuk button, slider, switch)
- [x] `hmi-manager.js` — render, setter, getter, layout serialization
- [x] `hmi-preview.js` — design-time preview untuk 3 SET block
- [x] `manifest.js` — 6 entry baru terdaftar
- [x] CSS untuk button, slider, switch di `index.html`
- [x] Bug 1
- [x] Bug 2
- [x] Bug 3
- [x] Bug 4
- [x] Manual test: SET block → preview widget muncul di design mode
- [x] Manual test: Run program → button clickable, slider draggable, switch toggleable
- [x] Manual test: GET block membaca state interaksi user dengan benar
- [x] Manual test: `while(true)` loop di Main Program tidak freeze UI
- [x] Manual test: Save/load workspace — widget positions preserved