feat: web UI chat render, panels, presence + analytics

backend/src/utils/read/read_receipts.py

@@ -0,0 +1,10 @@
+import asyncpg
+
+
+async def read_up_to(pool: asyncpg.Pool, account_id: int, chat_id: int) -> int | None:
+    return await pool.fetchval(
+        "SELECT max(message_id) FROM read_receipts "
+        "WHERE account_id = $1 AND chat_id = $2 AND kind = 'read'",
+        account_id,
+        chat_id,
+    )