rebrand: rename VoiceBox to TalkBox throughout codebase

- All 'voicebox'/'Voicebox'/'VOICEBOX' strings replaced with 'talkbox'/'TalkBox'/'TALKBOX'
- Port changed from 17493 to 17494 (avoids conflict with upstream VoiceBox)
- MCP tool namespace: voicebox.* -> talkbox.*
- App bundle ID: sh.voicebox.app -> com.talkbox.app
- Binary names: voicebox-server -> talkbox-server, voicebox-mcp -> talkbox-mcp
- Docker user/group: voicebox -> talkbox
- Database: voicebox.db -> talkbox.db
- Env vars: VOICEBOX_* -> TALKBOX_*
- Asset files renamed: voicebox-logo.* -> talkbox-logo.*, etc.
- External binaries in tauri.conf.json updated to talkbox-server/talkbox-mcp

backend/routes/health.py

@@ -29,7 +29,7 @@ async def root():
     index = _frontend_dir / "index.html"
     if index.is_file():
         return FileResponse(index, media_type="text/html")
-    return {"message": "voicebox API", "version": __version__}
+    return {"message": "talkbox API", "version": __version__}
 
 
 @router.post("/shutdown")
@@ -185,7 +185,7 @@ async def health():
         gpu_type=gpu_type,
         vram_used_mb=vram_used,
         backend_type=backend_type,
-        backend_variant=os.environ.get("VOICEBOX_BACKEND_VARIANT", default_variant),
+        backend_variant=os.environ.get("TALKBOX_BACKEND_VARIANT", default_variant),
         supports_rocm=is_amd_gpu_windows(),
         gpu_compatibility_warning=gpu_compat_warning,
     )
@@ -211,7 +211,7 @@ async def filesystem_health():
         writable = False
         error = None
         if exists:
-            probe = dir_path / ".voicebox_probe"
+            probe = dir_path / ".talkbox_probe"
             try:
                 probe.write_text("ok")
                 probe.unlink()