feat(im): Add user-owned IM channel connections (#3487)

* Add user-owned IM channel connections

* Fix dev startup and channel connect popup

* Use async channel connect flow

* Harden dev service daemon startup

* Support local IM channel connections

* Align IM connections with local channels

* Fix safe user id digest algorithm

* Address Copilot IM channel feedback

* Address IM channel review comments

* Support all integrated IM channel connections

* Format additional channel connection tests

* Keep unavailable channel connect buttons clickable

* Fix IM channel provider icons

* Add runtime setup for enabled IM channels

* Guard global shortcut key handling

* Keep configured IM channels editable

* Avoid password autofill for channel secrets

* Make channel threads visible to connection owners

* Persist IM runtime config locally

* Allow disconnecting runtime IM channels

* Route no-auth channel sessions to local user

* Use default user for auth-disabled local mode

* Show IM channel source on threads

* Prefill IM channel runtime config

* Reflect IM channel runtime health

* Ignore Feishu message read events

* Ignore Feishu non-content message events

* Let setup wizard enable IM channels

* Fix frontend formatting after merge

* Stabilize backend tests without local config

* Isolate channel runtime config tests

* Address channel connection review comments

* Use sha256 user buckets with legacy migration

* Ensure runtime IM channels are ready after restart

* Persist disconnected IM channel state

* Address channel connection review comments

* Address channel connection review findings

Frontend connect flow:
- Open the runtime-config dialog only when a provider still needs
  credentials; configured providers go straight to the connect flow, so
  the binding-code/deep-link path is reachable from the UI again.
- After saving credentials, continue into the connect flow when a user
  binding is still required (multi-user mode) instead of stopping at a
  "Connected" toast.
- Extract shared provider-state helpers to core/channels/provider-state
  and add unit + e2e coverage for the direct-connect and
  configure-then-connect paths.

Provider status semantics:
- Report connection_status from the user's newest connection row;
  with no binding it is not_connected, except in auth-disabled local
  mode where a configured running channel is effectively connected.

Concurrency and event-loop correctness:
- Offload ChannelRuntimeConfigStore construction and writes, channel
  service construction, and Slack connection replies to threads; add a
  tests/blocking_io/ anchor for the runtime-config handlers.
- Consume binding codes with a conditional UPDATE so a code can only be
  used once under concurrent workers; retry upsert_connection as an
  update when a concurrent insert wins the unique constraint.
- Serialize ensure_channel_ready per channel so concurrent provider
  polls cannot double-start a channel worker.

Config and migration hardening:
- Stop mutating the get_app_config()-cached Telegram provider config;
  the runtime store now owns the UI-entered bot username.
- Register channel_connections in STARTUP_ONLY_FIELDS with the
  standardized startup-only Field description.
- Match the legacy unsafe-id bucket by recomputing its exact SHA-1 name
  so another user's same-prefix bucket can never be migrated.
- Remove the unused Telegram process_webhook_update path and document
  src/core/channels in the frontend docs.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* Address PR review comments on authz scoping and channel runtime

Security (review feedback from ShenAC-SAC):
- Scope internal-token callers to the connection owner carried in
  X-DeerFlow-Owner-User-Id instead of bypassing owner checks outright,
  in both require_permission(owner_check=True) and the stateless run
  endpoints. Internal callers keep access to their own and
  shared/legacy threads, and may claim a default-owned channel thread
  for its real owner, but a leaked internal token no longer grants
  cross-user thread access.
- Require admin privileges for POST/DELETE /api/channels/{provider}/
  runtime-config: runtime credentials and channel workers are
  instance-wide shared state (same model as the MCP config API).
  Read-only provider listing stays available to all users.

Performance (review feedback from willem-bd):
- Skip the redundant thread channel-metadata PATCH after the first
  successful backfill per thread.
- Reuse the per-connection Slack WebClient until its token changes
  instead of constructing one per outbound message.
- Reconcile channel readiness for all providers concurrently in
  GET /api/channels/providers.

Also resolve the code-quality unused-import flag in the blocking-io
anchor by pre-importing the channel service via importlib.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* Fix prettier formatting in provider-state test

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* Reconcile UI runtime channel config with config reload on restart

Main now reloads a channel's config.yaml entry on restart_channel()
(#3514, issue #3497). Adapt the user-owned connection flow to coexist:

- configure_channel() restarts with reload_config=False — the caller
  just supplied the authoritative config (browser-entered credentials
  that are never written to config.yaml), so a file reload must not
  clobber it with the stale on-disk entry.
- _load_channel_config() re-applies the UI runtime-store overlay used
  at startup, so an operator-triggered restart keeps browser-entered
  credentials for channels without a config.yaml entry and does not
  resurrect a channel disconnected from the UI.
- Offload the reload's disk IO (config.yaml + runtime store) with
  asyncio.to_thread, matching the blocking-IO policy on this branch.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

backend/tests/blocking_io/test_channel_runtime_config_store.py

@@ -0,0 +1,106 @@
+"""Regression anchors: channel runtime-config handlers must not block the event loop.
+
+``configure_channel_provider_runtime`` and ``disconnect_channel_provider_runtime``
+persist UI-entered channel credentials through ``ChannelRuntimeConfigStore``,
+whose construction reads its JSON file and whose setters rewrite it
+(``json.dump`` + ``Path.replace`` + ``chmod``). The handlers offload both via
+``asyncio.to_thread``; if that regresses back onto the event loop, the strict
+Blockbuster gate raises ``BlockingError`` and these tests fail.
+
+The handlers are invoked directly with a minimal Starlette ``Request`` so the
+surface under test is exactly the router's own IO, mirroring
+``test_agents_router``. Test-side seeding/inspection is offloaded with
+``asyncio.to_thread``.
+"""
+
+from __future__ import annotations
+
+import asyncio
+import importlib
+from types import SimpleNamespace
+from uuid import UUID
+
+import pytest
+from fastapi import FastAPI, Request
+
+from app.channels.runtime_config_store import ChannelRuntimeConfigStore
+from app.gateway.routers.channel_connections import (
+    ChannelRuntimeConfigRequest,
+    configure_channel_provider_runtime,
+    disconnect_channel_provider_runtime,
+)
+from deerflow.config.app_config import AppConfig, reset_app_config, set_app_config
+from deerflow.config.channel_connections_config import ChannelConnectionsConfig
+
+# Pre-import: the handlers import this module lazily; the import's file IO
+# must happen at collection time, not on the event loop under the gate.
+importlib.import_module("app.channels.service")
+
+pytestmark = pytest.mark.asyncio
+
+
+@pytest.fixture(autouse=True)
+def _stub_app_config():
+    set_app_config(AppConfig.model_validate({"sandbox": {"use": "deerflow.sandbox.local:LocalSandboxProvider"}}))
+    yield
+    reset_app_config()
+
+
+def _make_request(tmp_path) -> Request:
+    app = FastAPI()
+    app.state.channel_connections_config = ChannelConnectionsConfig.model_validate(
+        {
+            "enabled": True,
+            "slack": {"enabled": True},
+        }
+    )
+    app.state.channels_config = {}
+    app.state.channel_connection_repo = _FakeRepo()
+    store = ChannelRuntimeConfigStore(tmp_path / "channels" / "runtime-config.json")
+    app.state.channel_runtime_config_store = store
+    user = SimpleNamespace(id=UUID("11111111-2222-3333-4444-555555555555"), system_role="admin")
+    return Request({"type": "http", "app": app, "headers": [], "state": {"user": user}})
+
+
+class _FakeRepo:
+    async def list_connections(self, owner_user_id):
+        return []
+
+
+async def test_configure_runtime_channel_does_not_block_event_loop(tmp_path) -> None:
+    request = await asyncio.to_thread(_make_request, tmp_path)
+
+    response = await configure_channel_provider_runtime(
+        "slack",
+        ChannelRuntimeConfigRequest(values={"bot_token": "xoxb-ui", "app_token": "xapp-ui"}),
+        request,
+    )
+
+    assert response.provider == "slack"
+    store = request.app.state.channel_runtime_config_store
+    assert await asyncio.to_thread(store.get_provider_config, "slack") == {
+        "enabled": True,
+        "bot_token": "xoxb-ui",
+        "app_token": "xapp-ui",
+    }
+
+
+async def test_disconnect_runtime_channel_does_not_block_event_loop(tmp_path) -> None:
+    request = await asyncio.to_thread(_make_request, tmp_path)
+    store = request.app.state.channel_runtime_config_store
+    await asyncio.to_thread(
+        store.set_provider_config,
+        "slack",
+        {"enabled": True, "bot_token": "xoxb-ui", "app_token": "xapp-ui"},
+    )
+    request.app.state.channels_config = {
+        "slack": {"enabled": True, "bot_token": "xoxb-ui", "app_token": "xapp-ui"},
+    }
+
+    response = await disconnect_channel_provider_runtime("slack", request)
+
+    assert response.provider == "slack"
+    assert await asyncio.to_thread(store.get_provider_config, "slack") == {
+        "enabled": False,
+        "_runtime_disabled": True,
+    }