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/test_auth_middleware.py

@@ -39,6 +39,8 @@ def test_public_paths(path: str):
         "/api/threads/123/uploads",
         "/api/agents",
         "/api/channels",
+        "/api/channels/providers",
+        "/api/channels/slack/connect",
         "/api/runs/stream",
         "/api/threads/123/runs",
         "/api/v1/auth/me",
@@ -183,7 +185,7 @@ def _make_auth_csrf_app():
 
 @pytest.fixture
 def client(monkeypatch):
-    monkeypatch.delenv("DEER_FLOW_AUTH_DISABLED", raising=False)
+    monkeypatch.setenv("DEER_FLOW_AUTH_DISABLED", "")
     return TestClient(_make_app())
 
 
@@ -221,7 +223,7 @@ def test_auth_disabled_allows_protected_path_without_cookie(monkeypatch):
     assert res.json() == {"models": []}
 
 
-def test_auth_disabled_stamps_e2e_admin_user_without_cookie(monkeypatch):
+def test_auth_disabled_stamps_default_admin_user_without_cookie(monkeypatch):
     monkeypatch.setenv("DEER_FLOW_AUTH_DISABLED", "1")
     client = TestClient(_make_app())
 
@@ -229,10 +231,10 @@ def test_auth_disabled_stamps_e2e_admin_user_without_cookie(monkeypatch):
 
     assert res.status_code == 200
     assert res.json() == {
-        "id": "e2e-user",
-        "email": "e2e@test.local",
+        "id": "default",
+        "email": "default@test.local",
         "system_role": "admin",
-        "context_user_id": "e2e-user",
+        "context_user_id": "default",
     }
 
 
@@ -244,8 +246,8 @@ def test_auth_disabled_auth_me_reuses_middleware_user_without_cookie(monkeypatch
 
     assert res.status_code == 200
     assert res.json() == {
-        "id": "e2e-user",
-        "email": "e2e@test.local",
+        "id": "default",
+        "email": "default@test.local",
         "system_role": "admin",
         "needs_setup": False,
     }
@@ -329,7 +331,7 @@ def test_auth_disabled_startup_warning_when_effective(monkeypatch, caplog):
         warn_if_auth_disabled_enabled()
 
     assert "authentication is bypassed" in caplog.text
-    assert "e2e-user" in caplog.text
+    assert "default" in caplog.text
 
 
 def test_auth_disabled_startup_warning_suppressed_in_explicit_production_env(monkeypatch, caplog):
@@ -348,7 +350,8 @@ def test_protected_path_with_junk_cookie_rejected(client):
     """Junk cookie → 401. Middleware strictly validates the JWT now
     (AUTH_TEST_PLAN test 7.5.8); it no longer silently passes bad
     tokens through to the route handler."""
-    res = client.get("/api/models", cookies={"access_token": "some-token"})
+    client.cookies.set("access_token", "some-token")
+    res = client.get("/api/models")
     assert res.status_code == 401