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

app/src/lib/hooks/useProfiles.ts

@@ -126,11 +126,11 @@ export function useExportProfile() {
       // Get profile name for filename
       const profile = await apiClient.getProfile(profileId);
       const safeName = profile.name.replace(/[^a-z0-9]/gi, '-').toLowerCase();
-      const filename = `profile-${safeName}.voicebox.zip`;
+      const filename = `profile-${safeName}.talkbox.zip`;
 
       await platform.filesystem.saveFile(filename, blob, [
         {
-          name: 'Voicebox Profile',
+          name: 'TalkBox Profile',
           extensions: ['zip'],
         },
       ]);