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

package.json

@@ -1,5 +1,5 @@
 {
-  "name": "voicebox",
+  "name": "talkbox",
   "version": "0.5.0",
   "private": true,
   "workspaces": [
@@ -12,14 +12,14 @@
     "dev": "bun run setup:dev && cd tauri && bun run tauri dev",
     "dev:web": "cd web && bun run dev",
     "dev:landing": "cd landing && bun run dev",
-    "dev:server": "uvicorn backend.main:app --reload --port 17493",
+    "dev:server": "uvicorn backend.main:app --reload --port 17494",
     "setup:dev": "bun run scripts/setup-dev-sidecar.js",
     "build": "./scripts/build-server.sh && cd tauri && bun run tauri build",
     "build:web": "cd web && bun run build",
     "build:landing": "cd landing && bun run build",
     "build:release": "./scripts/prepare-release.sh",
     "generate:api": "./scripts/generate-api.sh",
-    "generate:keys": "cd tauri && bun tauri signer generate -w ~/.tauri/voicebox.key",
+    "generate:keys": "cd tauri && bun tauri signer generate -w ~/.tauri/talkbox.key",
     "build:server": "./scripts/build-server.sh",
     "update:icons": "./scripts/update-icons.sh",
     "convert:assets": "./scripts/convert-assets.sh",