fix(ui+spice+example): interactive wokwi components, NTC formula, photoresistor alias

Three independent fixes uncovered during a systematic example-by-example
audit (plan/full_test_plan/):

1. DynamicComponent.handleMouseDown was calling e.stopPropagation()
   unconditionally in the capture phase. That swallowed pointerdown
   BEFORE wokwi-potentiometer / pushbutton / slide-switch / joystick
   could see it, so the rotary knob would not rotate and buttons
   wouldn't press even with a real OS mouse. Now we skip the swallow
   when the click target is an inner wokwi-* element during a live
   simulation, letting the wokwi component own its own pointerdown
   while still allowing the canvas drag-to-rearrange flow on the
   wrapper / non-interactive surface.

2. examples.ts uno-ntc (and pico-ntc) sketch had the NTC divider
   formula inverted relative to both the SPICE mapper topology
   (VCC -> R_NTC -> A1 -> R_pull -> GND, the standard module wiring)
   and real wokwi-ntc-temperature-sensor modules. Moving the slider
   to 60 C made the firmware print -3.42 C. Flipped the formula to
   r = SERIES_R * (VCC - v) / v. Now slider 60 C -> Serial reports
   60.12 C and A1 voltmeter shows 4.00 V.

3. componentToSpice.ts photoresistor mapper was only registered under
   the bare key `photoresistor`, but example components use the
   metadataId `photoresistor-sensor`. Added an alias so the LDR +
   pull-down divider gets emitted for the real component instance.

All three reproduce visually in seconds; documented per-example in
plan/full_test_plan/examples/.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

frontend/src/components/DynamicComponent.tsx

@@ -276,12 +276,37 @@ export const DynamicComponent: React.FC<DynamicComponentProps> = ({
    */
   const handleMouseDown = useCallback(
     (e: React.MouseEvent) => {
-      if (onMouseDown) {
-        e.stopPropagation();
-        onMouseDown(e);
+      if (!onMouseDown) return;
+      // Don't swallow the pointerdown when the user is interacting with a
+      // live wokwi component (rotating a potentiometer knob, pressing a
+      // pushbutton, toggling a slide-switch, dragging the joystick stick,
+      // etc.). The wokwi-elements internally use pointerdown/move/up on
+      // their shadow-DOM SVGs; if we call stopPropagation() in the capture
+      // phase here, that internal logic NEVER receives the event and the
+      // knob can't rotate, the button never reports pressed, etc.
+      //
+      // The canvas's drag-to-rearrange flow still works: the user can grab
+      // the component WRAPPER (its padding/border) or any non-interactive
+      // part of the body. For interactive parts the wokwi component owns
+      // the click — same UX as Wokwi/Tinkercad.
+      //
+      // We additionally allow the canvas drag when the simulation is NOT
+      // running (interactionRunning=false): the user is in "edit mode"
+      // arranging the board, so capturing the click into a canvas drag
+      // is the correct behaviour even on interactive components.
+      const target = e.target as HTMLElement;
+      const targetIsInteractive =
+        isInteractive &&
+        interactionRunning &&
+        target.tagName.toLowerCase().startsWith('wokwi-');
+      if (targetIsInteractive) {
+        // Let the wokwi component own this pointerdown.
+        return;
       }
+      e.stopPropagation();
+      onMouseDown(e);
     },
-    [onMouseDown],
+    [onMouseDown, isInteractive, interactionRunning],
   );
 
   const handleDoubleClick = useCallback(

frontend/src/data/examples.ts

@@ -5185,7 +5185,13 @@ const float NOM_TEMP_K  = 298.15;   // 25 °C in Kelvin
 float readTempC() {
   int   raw  = analogRead(NTC_PIN);
   float v    = raw * (VCC / 1023.0);
-  float r    = SERIES_R * v / (VCC - v);  // voltage divider
+  // Voltage divider topology used by standard NTC modules and by Velxio's
+  // wokwi-ntc-temperature-sensor: VCC → R_NTC → A1 → R_pull (10k) → GND.
+  // Higher temperature → R_NTC drops → V rises, so the NTC resistance is
+  //   r = R_pull * (VCC - v) / v
+  // Using the inverted form (r = R_pull * v / (VCC - v)) gives the wrong
+  // sign and Steinhart-Hart returns negative temperatures for hot inputs.
+  float r    = SERIES_R * (VCC - v) / v;
   // Steinhart–Hart simplified equation
   float st   = log(r / NOM_R) / B_COEFF + 1.0 / NOM_TEMP_K;
   return (1.0 / st) - 273.15;
@@ -5514,7 +5520,8 @@ const float NOM_TEMP_K = 298.15; // 25 °C
 float readTempC() {
   int   raw = analogRead(NTC_PIN);
   float v   = raw * (VCC / 1023.0);
-  float r   = SERIES_R * v / (VCC - v);
+  // VCC → R_NTC → A1 → R_pull → GND  (standard NTC module topology)
+  float r   = SERIES_R * (VCC - v) / v;
   float st  = log(r / NOM_R) / B_COEFF + 1.0 / NOM_TEMP_K;
   return (1.0 / st) - 273.15;
 }

frontend/src/simulation/spice/componentToSpice.ts

@@ -1220,6 +1220,14 @@ for (const [presetId, baseId] of Object.entries(PASSIVE_PRESETS)) {
   MAPPERS[presetId] = MAPPERS[baseId];
 }
 
+// Alias: metadata id for the wokwi-photoresistor-sensor breakout is
+// `photoresistor-sensor`, but the mapper is registered under the short
+// name `photoresistor` (matches the bare LDR/discrete element). Without
+// this alias, any example that drops a photoresistor sensor on the
+// canvas gets a null mapping → no R_ldr / R_pull emitted → A0 net
+// floats → analogRead returns 0 even though the divider should solve.
+MAPPERS['photoresistor-sensor'] = MAPPERS['photoresistor'];
+
 /**
  * Public entry: map one Velxio component to SPICE cards.
  * Returns null if we have no mapping for this metadataId (caller should