refactor(config): eliminate global mutable state, wire DeerFlowContext into runtime

- Freeze all config models (AppConfig + 15 sub-configs) with frozen=True
- Purify from_file() — remove 9 load_*_from_dict() side-effect calls
- Replace mtime/reload/push/pop machinery with single ContextVar + init_app_config()
- Delete 10 sub-module globals and their getters/setters/loaders
- Migrate 50+ consumers from get_*_config() to get_app_config().xxx

- Expand DeerFlowContext: app_config + thread_id + agent_name (frozen dataclass)
- Wire into Gateway runtime (worker.py) and DeerFlowClient via context= parameter
- Remove sandbox_id from runtime.context — flows through ThreadState.sandbox only
- Middleware/tools access runtime.context directly via Runtime[DeerFlowContext] generic
- resolve_context() retained at server entry points for LangGraph Server fallback

backend/packages/harness/deerflow/runtime/runs/worker.py

@@ -21,6 +21,8 @@ import inspect
 import logging
 from typing import Any, Literal
 
+from deerflow.config.app_config import AppConfig
+from deerflow.config.deer_flow_context import DeerFlowContext
 from deerflow.runtime.serialization import serialize
 from deerflow.runtime.stream_bridge import StreamBridge
 
@@ -98,17 +100,14 @@ async def run_agent(
 
         # 3. Build the agent
         from langchain_core.runnables import RunnableConfig
-        from langgraph.runtime import Runtime
 
-        # Inject runtime context so middlewares can access thread_id
-        # (langgraph-cli does this automatically; we must do it manually)
-        runtime = Runtime(context={"thread_id": thread_id}, store=store)
-        # If the caller already set a ``context`` key (LangGraph >= 0.6.0
-        # prefers it over ``configurable`` for thread-level data), make
-        # sure ``thread_id`` is available there too.
-        if "context" in config and isinstance(config["context"], dict):
-            config["context"].setdefault("thread_id", thread_id)
-        config.setdefault("configurable", {})["__pregel_runtime"] = runtime
+        # Construct typed context for the agent run.
+        # LangGraph's astream(context=...) injects this into Runtime.context
+        # so middleware/tools can access it via resolve_context().
+        deer_flow_context = DeerFlowContext(
+            app_config=AppConfig.current(),
+            thread_id=thread_id,
+        )
 
         runnable_config = RunnableConfig(**config)
         agent = agent_factory(config=runnable_config)
@@ -155,7 +154,7 @@ async def run_agent(
         if len(lg_modes) == 1 and not stream_subgraphs:
             # Single mode, no subgraphs: astream yields raw chunks
             single_mode = lg_modes[0]
-            async for chunk in agent.astream(graph_input, config=runnable_config, stream_mode=single_mode):
+            async for chunk in agent.astream(graph_input, config=runnable_config, context=deer_flow_context, stream_mode=single_mode):
                 if record.abort_event.is_set():
                     logger.info("Run %s abort requested — stopping", run_id)
                     break
@@ -166,6 +165,7 @@ async def run_agent(
             async for item in agent.astream(
                 graph_input,
                 config=runnable_config,
+                context=deer_flow_context,
                 stream_mode=lg_modes,
                 subgraphs=stream_subgraphs,
             ):

backend/packages/harness/deerflow/runtime/store/async_provider.py

@@ -23,7 +23,7 @@ from collections.abc import AsyncIterator
 
 from langgraph.store.base import BaseStore
 
-from deerflow.config.app_config import get_app_config
+from deerflow.config.app_config import AppConfig
 from deerflow.runtime.store.provider import POSTGRES_CONN_REQUIRED, POSTGRES_STORE_INSTALL, SQLITE_STORE_INSTALL, ensure_sqlite_parent_dir, resolve_sqlite_conn_str
 
 logger = logging.getLogger(__name__)
@@ -100,7 +100,7 @@ async def make_store() -> AsyncIterator[BaseStore]:
     Yields an :class:`~langgraph.store.memory.InMemoryStore` when no
     ``checkpointer`` section is configured (emits a WARNING in that case).
     """
-    config = get_app_config()
+    config = AppConfig.current()
 
     if config.checkpointer is None:
         from langgraph.store.memory import InMemoryStore

backend/packages/harness/deerflow/runtime/store/provider.py

@@ -26,7 +26,7 @@ from collections.abc import Iterator
 
 from langgraph.store.base import BaseStore
 
-from deerflow.config.app_config import get_app_config
+from deerflow.config.app_config import AppConfig
 from deerflow.runtime.store._sqlite_utils import ensure_sqlite_parent_dir, resolve_sqlite_conn_str
 
 logger = logging.getLogger(__name__)
@@ -115,19 +115,10 @@ def get_store() -> BaseStore:
     if _store is not None:
         return _store
 
-    # Lazily load app config, mirroring the checkpointer singleton pattern so
-    # that tests that set the global checkpointer config explicitly remain isolated.
-    from deerflow.config.app_config import _app_config
-    from deerflow.config.checkpointer_config import get_checkpointer_config
-
-    config = get_checkpointer_config()
-
-    if config is None and _app_config is None:
-        try:
-            get_app_config()
-        except FileNotFoundError:
-            pass
-        config = get_checkpointer_config()
+    try:
+        config = AppConfig.current().checkpointer
+    except (LookupError, FileNotFoundError):
+        config = None
 
     if config is None:
         from langgraph.store.memory import InMemoryStore
@@ -176,7 +167,7 @@ def store_context() -> Iterator[BaseStore]:
     Yields an :class:`~langgraph.store.memory.InMemoryStore` when no
     checkpointer is configured in *config.yaml*.
     """
-    config = get_app_config()
+    config = AppConfig.current()
     if config.checkpointer is None:
         from langgraph.store.memory import InMemoryStore
 

backend/packages/harness/deerflow/runtime/stream_bridge/async_provider.py

@@ -17,7 +17,7 @@ import contextlib
 import logging
 from collections.abc import AsyncIterator
 
-from deerflow.config.stream_bridge_config import get_stream_bridge_config
+from deerflow.config.app_config import AppConfig
 
 from .base import StreamBridge
 
@@ -32,7 +32,7 @@ async def make_stream_bridge(config=None) -> AsyncIterator[StreamBridge]:
     provided and nothing is set globally.
     """
     if config is None:
-        config = get_stream_bridge_config()
+        config = AppConfig.current().stream_bridge
 
     if config is None or config.type == "memory":
         from deerflow.runtime.stream_bridge.memory import MemoryStreamBridge