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/tests/test_rocm_build.py

@@ -35,7 +35,7 @@ class TestRocmBuildArgs:
 
     def test_binary_name(self, captured_args):
         idx = captured_args.index("--name")
-        assert captured_args[idx + 1] == "voicebox-server-rocm"
+        assert captured_args[idx + 1] == "talkbox-server-rocm"
 
     def test_pack_mode_is_onedir(self, captured_args):
         assert "--onedir" in captured_args
@@ -91,8 +91,8 @@ class TestRocmBuildE2E:
         backend_dir = Path(__file__).parent.parent
         build_script = backend_dir / "build_binary.py"
         dist_dir = backend_dir / "dist"
-        binary_dir = dist_dir / "voicebox-server-rocm"
-        binary_exe = binary_dir / "voicebox-server-rocm.exe"
+        binary_dir = dist_dir / "talkbox-server-rocm"
+        binary_exe = binary_dir / "talkbox-server-rocm.exe"
 
         # Clean previous dist if it exists to ensure a fresh build
         if binary_dir.exists():