feat: add web gateway — browser-based chat UI over WebSocket

New platform adapter that serves a full-featured chat interface via HTTP.
Enables access from any device on the network (phone, tablet, desktop).

Features:
- aiohttp server with WebSocket real-time messaging
- Token-based authentication
- Markdown rendering (marked.js) + code highlighting (highlight.js)
- Voice recording via MediaRecorder API + STT transcription
- Image, voice, and document display
- Typing indicator + message editing (streaming support)
- Mobile responsive dark theme
- Auto-reconnect on disconnect
- Media file cleanup (24h TTL)

Config: WEB_UI_ENABLED=true, WEB_UI_PORT=8765, WEB_UI_TOKEN=<token>
No new dependencies — uses aiohttp already in [messaging] extra.

gateway/config.py

@@ -31,6 +31,7 @@ class Platform(Enum):
     SIGNAL = "signal"
     HOMEASSISTANT = "homeassistant"
     EMAIL = "email"
+    WEB = "web"
 
 
 @dataclass
@@ -176,6 +177,9 @@ class GatewayConfig:
             # Email uses extra dict for config (address + imap_host + smtp_host)
             elif platform == Platform.EMAIL and config.extra.get("address"):
                 connected.append(platform)
+            # Web UI uses enabled flag only
+            elif platform == Platform.WEB:
+                connected.append(platform)
         return connected
     
     def get_home_channel(self, platform: Platform) -> Optional[HomeChannel]:
@@ -466,6 +470,18 @@ def _apply_env_overrides(config: GatewayConfig) -> None:
                 name=os.getenv("EMAIL_HOME_ADDRESS_NAME", "Home"),
             )
 
+    # Web UI
+    web_enabled = os.getenv("WEB_UI_ENABLED", "").lower() in ("true", "1", "yes")
+    if web_enabled:
+        if Platform.WEB not in config.platforms:
+            config.platforms[Platform.WEB] = PlatformConfig()
+        config.platforms[Platform.WEB].enabled = True
+        config.platforms[Platform.WEB].extra.update({
+            "port": int(os.getenv("WEB_UI_PORT", "8765")),
+            "host": os.getenv("WEB_UI_HOST", "0.0.0.0"),
+            "token": os.getenv("WEB_UI_TOKEN", ""),
+        })
+
     # Session settings
     idle_minutes = os.getenv("SESSION_IDLE_MINUTES")
     if idle_minutes:

gateway/run.py

@@ -829,6 +829,13 @@ class GatewayRunner:
                 return None
             return EmailAdapter(config)
 
+        elif platform == Platform.WEB:
+            from gateway.platforms.web import WebAdapter, check_web_requirements
+            if not check_web_requirements():
+                logger.warning("Web: aiohttp not installed. Run: pip install aiohttp")
+                return None
+            return WebAdapter(config)
+
         return None
     
     def _is_user_authorized(self, source: SessionSource) -> bool:
@@ -848,6 +855,11 @@ class GatewayRunner:
         if source.platform == Platform.HOMEASSISTANT:
             return True
 
+        # Web UI users are authenticated via token at the WebSocket level.
+        # No additional allowlist check needed.
+        if source.platform == Platform.WEB:
+            return True
+
         user_id = source.user_id
         if not user_id:
             return False