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

scripts/rocm-entrypoint.sh

@@ -10,6 +10,6 @@ for dev in /dev/kfd /dev/dri/render*; do
         grp="gpu$gid"
         groupadd -g "$gid" "$grp"
     }
-    usermod -aG "$grp" voicebox
+    usermod -aG "$grp" talkbox
 done
-exec gosu voicebox "$@"
+exec gosu talkbox "$@"