Merge refactor/config-deerflow-context into release/2.0-rc

Cherry-pick PR #2271's config refactor onto release/2.0-rc.
Used 'git merge -X theirs' to auto-resolve content conflicts in favor of
the PR's design (frozen AppConfig + explicit-parameter passing).

Limitations:
- Release-only changes that overlapped with PR's refactor in 119 files
  are NOT preserved — those files reflect PR's version. Follow-up commits
  on this branch will need to re-apply release-only modifications where
  meaningful.
- See PR #2271 for design rationale.

backend/app/channels/feishu.py

@@ -375,7 +375,9 @@ class FeishuChannel(Channel):
         virtual_path = f"{VIRTUAL_PATH_PREFIX}/uploads/{resolved_target.name}"
 
         try:
-            sandbox_provider = get_sandbox_provider()
+            from deerflow.config.app_config import AppConfig
+
+            sandbox_provider = get_sandbox_provider(AppConfig.from_file())
             sandbox_id = sandbox_provider.acquire(thread_id)
             if sandbox_id != "local":
                 sandbox = sandbox_provider.get(sandbox_id)

backend/app/channels/manager.py

@@ -17,8 +17,6 @@ from langgraph_sdk.errors import ConflictError
 from app.channels.commands import KNOWN_CHANNEL_COMMANDS
 from app.channels.message_bus import InboundMessage, InboundMessageType, MessageBus, OutboundMessage, ResolvedAttachment
 from app.channels.store import ChannelStore
-from app.gateway.csrf_middleware import CSRF_COOKIE_NAME, CSRF_HEADER_NAME, generate_csrf_token
-from app.gateway.internal_auth import create_internal_auth_headers
 from deerflow.runtime.user_context import get_effective_user_id
 
 logger = logging.getLogger(__name__)

backend/app/channels/service.py

@@ -4,13 +4,16 @@ from __future__ import annotations
 
 import logging
 import os
-from typing import Any
+from typing import TYPE_CHECKING, Any
 
 from app.channels.base import Channel
 from app.channels.manager import DEFAULT_GATEWAY_URL, DEFAULT_LANGGRAPH_URL, ChannelManager
 from app.channels.message_bus import MessageBus
 from app.channels.store import ChannelStore
 
+if TYPE_CHECKING:
+    from deerflow.config.app_config import AppConfig
+
 logger = logging.getLogger(__name__)
 
 # Channel name → import path for lazy loading
@@ -75,14 +78,11 @@ class ChannelService:
         self._running = False
 
     @classmethod
-    def from_app_config(cls) -> ChannelService:
-        """Create a ChannelService from the application config."""
-        from deerflow.config.app_config import get_app_config
-
-        config = get_app_config()
+    def from_app_config(cls, app_config: AppConfig) -> ChannelService:
+        """Create a ChannelService from an explicit application config."""
         channels_config = {}
         # extra fields are allowed by AppConfig (extra="allow")
-        extra = config.model_extra or {}
+        extra = app_config.model_extra or {}
         if "channels" in extra:
             channels_config = extra["channels"]
         return cls(channels_config=channels_config)
@@ -201,12 +201,12 @@ def get_channel_service() -> ChannelService | None:
     return _channel_service
 
 
-async def start_channel_service() -> ChannelService:
+async def start_channel_service(app_config: AppConfig) -> ChannelService:
     """Create and start the global ChannelService from app config."""
     global _channel_service
     if _channel_service is not None:
         return _channel_service
-    _channel_service = ChannelService.from_app_config()
+    _channel_service = ChannelService.from_app_config(app_config)
     await _channel_service.start()
     return _channel_service