feat: add chat group daily summarizer

- Telegram collector (Telethon MTProto) with checkpoint-based message fetching
- Claude API summarization via proxy (haiku model)
- Dashboard page with date picker, markdown summary, raw message drill-down
- Separate container lifecycle from dashboard for stable Telethon sessions
- Shared SQLite DB mounted read-only into dashboard

dashboard/backend/routers/chat_summary.py

@@ -0,0 +1,41 @@
+from fastapi import APIRouter, HTTPException
+import aiosqlite
+from config import CHAT_SUMMARY_DB
+
+router = APIRouter()
+
+async def _db():
+    return aiosqlite.connect(CHAT_SUMMARY_DB)
+
+@router.get("/dates")
+async def list_dates():
+    async with await _db() as db:
+        cursor = await db.execute("SELECT date FROM summaries ORDER BY date DESC")
+        return [r[0] for r in await cursor.fetchall()]
+
+@router.get("/summary/{date}")
+async def get_summary(date: str):
+    async with await _db() as db:
+        cursor = await db.execute("SELECT content, created_at FROM summaries WHERE date=?", (date,))
+        row = await cursor.fetchone()
+    if not row:
+        raise HTTPException(404, "No summary for this date")
+    return {"date": date, "content": row[0], "created_at": row[1]}
+
+@router.get("/messages/{date}")
+async def get_messages(date: str):
+    async with await _db() as db:
+        cursor = await db.execute(
+            "SELECT group_name, sender_name, text, timestamp FROM messages WHERE date(timestamp)=? ORDER BY timestamp",
+            (date,)
+        )
+        return [{"group": r[0], "sender": r[1], "text": r[2], "time": r[3]} for r in await cursor.fetchall()]
+
+@router.post("/trigger")
+async def trigger_summary():
+    import os
+    trigger_path = os.environ.get("CHAT_SUMMARY_TRIGGER", "/app/data/chat-summarizer/trigger")
+    os.makedirs(os.path.dirname(trigger_path), exist_ok=True)
+    with open(trigger_path, "w") as f:
+        f.write("1")
+    return {"status": "triggered"}