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_requirements.py

@@ -65,8 +65,8 @@ class TestRocmRequirements:
 
     @pytest.mark.timeout(900)
     @pytest.mark.skipif(
-        not os.environ.get("VOICEBOX_TEST_ROCM_INSTALL"),
-        reason="Set VOICEBOX_TEST_ROCM_INSTALL=1 to run the heavy install test",
+        not os.environ.get("TALKBOX_TEST_ROCM_INSTALL"),
+        reason="Set TALKBOX_TEST_ROCM_INSTALL=1 to run the heavy install test",
     )
     def test_rocm_torch_installs_and_detects_amd(self, backend_dir):
         """