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/components/ServerSettings/ConnectionForm.tsx

@@ -77,9 +77,9 @@ export function ConnectionForm() {
                 <FormItem>
                   <FormLabel>Server URL</FormLabel>
                   <FormControl>
-                    <Input placeholder="http://127.0.0.1:17493" {...field} />
+                    <Input placeholder="http://127.0.0.1:17494" {...field} />
                   </FormControl>
-                  <FormDescription>Enter the URL of your voicebox backend server</FormDescription>
+                  <FormDescription>Enter the URL of your talkbox backend server</FormDescription>
                   <FormMessage />
                 </FormItem>
               )}