feat(06-01): add web channel type, Redis key, ORM models, migration, and tests

- Add ChannelType.WEB = 'web' to shared/models/message.py
- Add webchat_response_key() to shared/redis_keys.py
- Create WebConversation and WebConversationMessage ORM models (SQLAlchemy 2.0)
- Create migration 008_web_chat.py with RLS, indexes, and channel_type CHECK update
- Pop conversation_id/portal_user_id extras in handle_message before model_validate
- Add web case to _build_response_extras and _send_response (Redis pub-sub publish)
- Import webchat_response_key in orchestrator/tasks.py
- Write 19 unit tests covering CHAT-01 through CHAT-05 (all pass)

packages/orchestrator/orchestrator/tasks.py

@@ -77,7 +77,7 @@ from orchestrator.tools.registry import get_tools_for_agent
 from shared.config import settings
 from shared.db import async_session_factory, engine
 from shared.models.message import KonstructMessage
-from shared.redis_keys import escalation_status_key
+from shared.redis_keys import escalation_status_key, webchat_response_key
 from shared.rls import configure_rls_hook, current_tenant_id
 
 logger = logging.getLogger(__name__)
@@ -253,6 +253,11 @@ def handle_message(self, message_data: dict) -> dict:  # type: ignore[no-untyped
     phone_number_id: str = message_data.pop("phone_number_id", "") or ""
     bot_token: str = message_data.pop("bot_token", "") or ""
 
+    # Extract web channel extras before model validation
+    # The web WebSocket handler injects these alongside the normalized KonstructMessage fields
+    conversation_id: str = message_data.pop("conversation_id", "") or ""
+    portal_user_id: str = message_data.pop("portal_user_id", "") or ""
+
     try:
         msg = KonstructMessage.model_validate(message_data)
     except Exception as exc:
@@ -272,6 +277,11 @@ def handle_message(self, message_data: dict) -> dict:  # type: ignore[no-untyped
         "phone_number_id": phone_number_id,
         "bot_token": bot_token,
         "wa_id": wa_id,
+        # Web channel extras
+        "conversation_id": conversation_id,
+        "portal_user_id": portal_user_id,
+        # tenant_id for web channel response routing (web lacks a workspace_id in channel_connections)
+        "tenant_id": msg.tenant_id or "",
     }
 
     result = asyncio.run(_process_message(msg, extras=extras))
@@ -646,6 +656,13 @@ def _build_response_extras(
             "bot_token": extras.get("bot_token", "") or "",
             "wa_id": extras.get("wa_id", "") or "",
         }
+    elif channel_str == "web":
+        # Web channel: tenant_id comes from extras (set by handle_message from msg.tenant_id),
+        # not from channel_connections like Slack. conversation_id scopes the Redis pub-sub channel.
+        return {
+            "conversation_id": extras.get("conversation_id", "") or "",
+            "tenant_id": extras.get("tenant_id", "") or "",
+        }
     else:
         return dict(extras)
 
@@ -774,6 +791,31 @@ async def _send_response(
             text=text,
         )
 
+    elif channel_str == "web":
+        # Publish agent response to Redis pub-sub so the WebSocket handler can deliver it
+        web_conversation_id: str = extras.get("conversation_id", "") or ""
+        web_tenant_id: str = extras.get("tenant_id", "") or ""
+
+        if not web_conversation_id or not web_tenant_id:
+            logger.warning(
+                "_send_response: web channel missing conversation_id or tenant_id in extras"
+            )
+            return
+
+        response_channel = webchat_response_key(web_tenant_id, web_conversation_id)
+        publish_redis = aioredis.from_url(settings.redis_url)
+        try:
+            await publish_redis.publish(
+                response_channel,
+                json.dumps({
+                    "type": "response",
+                    "text": text,
+                    "conversation_id": web_conversation_id,
+                }),
+            )
+        finally:
+            await publish_redis.aclose()
+
     else:
         logger.warning(
             "_send_response: unsupported channel=%r — response not delivered", channel