fix: GET /bots/{bot_id} redirects to the bot's chat

bot_list.html linked each bot to /bots/{bot.id} but no GET handler
existed, so clicking a bot 404'd. Add a route that:

- 404s if the bot doesn't exist
- 303 -> /chats/chat_{bot_id} when the bot's chat exists
- 303 -> /bots/{bot_id}/kickoff otherwise (so a freshly-created bot
  links straight to its kickoff form)

Declared AFTER /bots/new and /bots/{bot_id}/kickoff in routing order
so the path-parameter route doesn't swallow the more specific paths
(FastAPI matches in declaration order).

chat/web/bots.py

@@ -7,7 +7,8 @@ from fastapi.templating import Jinja2Templates
 from chat.db.connection import open_db
 from chat.eventlog.log import append_event
 from chat.eventlog.projector import project
-from chat.state.entities import list_bots
+from chat.state.entities import get_bot, list_bots
+from chat.state.world import get_chat
 
 TEMPLATES = Jinja2Templates(directory=str(Path(__file__).resolve().parent.parent / "templates"))
 
@@ -113,6 +114,26 @@ async def bot_create(
     return RedirectResponse(url=f"/bots/{payload['id']}/kickoff", status_code=303)
 
 
+@router.get("/bots/{bot_id}")
+async def bot_detail(bot_id: str, conn=Depends(get_conn)):
+    """Click-through from the bots list. Routes to the bot's existing
+    chat when there is one (the v1 model is one-chat-per-host-bot,
+    keyed by ``chat_<bot_id>``), otherwise to the kickoff page so the
+    user can author the chat's opening state. 404 if the bot itself
+    doesn't exist.
+
+    Defined AFTER the ``/bots/new`` and ``/bots/{bot_id}/kickoff``
+    routes — FastAPI matches in declaration order, and a path
+    parameter would otherwise swallow ``/bots/new``.
+    """
+    if get_bot(conn, bot_id) is None:
+        raise HTTPException(status_code=404, detail="bot not found")
+    chat_id = f"chat_{bot_id}"
+    if get_chat(conn, chat_id) is not None:
+        return RedirectResponse(url=f"/chats/{chat_id}", status_code=303)
+    return RedirectResponse(url=f"/bots/{bot_id}/kickoff", status_code=303)
+
+
 @router.post("/bots/{bot_id}/reset")
 async def reset_bot_route(
     bot_id: str,