chore(manifest): make PWA mobile-friendly + better TWA copy

Three small fixes to frontend/public/manifest.webmanifest so the
Bubblewrap-generated TWA (and Add-to-Home-Screen PWA installs) feel
right on a phone:

  - orientation: landscape → any. Landscape-forced on a phone
    locks the device in side-grip whenever Velxio is foregrounded;
    the editor + simulator work fine in portrait too (the file
    explorer collapses gracefully). Tablets and desktops still
    default to landscape because they're naturally wider, so this
    only changes behaviour where the lock would actively hurt.
  - name: "Arduino Emulator" → "Circuit & Arduino Simulator".
    Matches the title tag + Open Graph copy that velxio.dev uses
    everywhere else and reflects the SPICE / ESP32 / RP2040 work
    the project has grown into since the original name was written.
  - description: was 'Free local Arduino emulator … No cloud, no
    latency.' That was true for the OSS self-host but misleading
    for an installed PWA that talks to velxio.dev. Rewritten to
    describe the actual product surface (the boards, the SPICE
    sim, "free and open source") without making a claim the live
    site can't keep.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/public/manifest.webmanifest

@@ -1,11 +1,11 @@
 {
-  "name": "Velxio — Arduino Emulator",
+  "name": "Velxio — Circuit & Arduino Simulator",
   "short_name": "Velxio",
-  "description": "Free local Arduino emulator with real AVR8 CPU emulation, 48+ electronic components, Monaco Editor, and Serial Monitor. No cloud, no latency.",
+  "description": "Online circuit and Arduino simulator. ESP32, RP2040, Pi Pico, ATtiny85, SPICE analog simulation, 100+ components. Free and open source.",
   "start_url": "/editor",
   "scope": "/",
   "display": "standalone",
-  "orientation": "landscape",
+  "orientation": "any",
   "background_color": "#0d0d0f",
   "theme_color": "#007acc",
   "categories": ["developer", "education", "productivity"],