feat: unified HomeAI dashboard — merge character + desktop into single app

Combines homeai-character (service status, character profiles, editor) and
homeai-desktop (chat with voice I/O) into homeai-dashboard on port 5173.

- 4-page sidebar layout: Dashboard, Chat, Characters, Editor
- Merged Vite middleware: health checks, service restart, bridge proxy
- Bridge upgraded to ThreadingHTTPServer (fixes LAN request queuing)
- TTS strips emojis before synthesis
- Updated start.sh with new launchd service names
- Added preload-models to startup sequence

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

homeai-dashboard/src/hooks/useSettings.js

@@ -0,0 +1,27 @@
+import { useState, useCallback } from 'react'
+import { DEFAULT_SETTINGS } from '../lib/constants'
+
+const STORAGE_KEY = 'homeai_dashboard_settings'
+
+function loadSettings() {
+  try {
+    const stored = localStorage.getItem(STORAGE_KEY)
+    return stored ? { ...DEFAULT_SETTINGS, ...JSON.parse(stored) } : { ...DEFAULT_SETTINGS }
+  } catch {
+    return { ...DEFAULT_SETTINGS }
+  }
+}
+
+export function useSettings() {
+  const [settings, setSettings] = useState(loadSettings)
+
+  const updateSetting = useCallback((key, value) => {
+    setSettings((prev) => {
+      const next = { ...prev, [key]: value }
+      localStorage.setItem(STORAGE_KEY, JSON.stringify(next))
+      return next
+    })
+  }, [])
+
+  return { settings, updateSetting }
+}