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/mcp_server/server.py

@@ -2,7 +2,7 @@
 
 The MCP endpoint lives at ``/mcp`` (Streamable HTTP transport). Modern MCP
 clients (Claude Code, Cursor, Windsurf, VS Code MCP extensions) connect
-directly via URL; older stdio-only clients use the ``voicebox-mcp`` shim
+directly via URL; older stdio-only clients use the ``talkbox-mcp`` shim
 binary bundled with the desktop app.
 """
 
@@ -23,12 +23,12 @@ logger = logging.getLogger(__name__)
 
 
 def build_mcp_server() -> FastMCP:
-    """Create the FastMCP instance with Voicebox tools registered."""
+    """Create the FastMCP instance with TalkBox tools registered."""
     mcp = FastMCP(
-        name="voicebox",
+        name="talkbox",
         instructions=(
-            "Voicebox is a local voice I/O layer. Use `voicebox.speak` to "
-            "play text in a voice profile, `voicebox.transcribe` for "
+            "TalkBox is a local voice I/O layer. Use `talkbox.speak` to "
+            "play text in a voice profile, `talkbox.transcribe` for "
             "audio→text, and the `list_*` tools to discover profiles and "
             "captures."
         ),
@@ -63,7 +63,7 @@ def mount_into(
 def compose_lifespan(*lifespans):
     """Combine multiple async context managers into a single FastAPI lifespan.
 
-    Used by ``create_app`` to run the existing Voicebox startup/shutdown
+    Used by ``create_app`` to run the existing TalkBox startup/shutdown
     together with FastMCP's session manager (which MUST run in the
     ASGI lifespan for Streamable HTTP to work).
     """