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/community/aio_sandbox/aio_sandbox_provider.py

@@ -25,7 +25,7 @@ except ImportError:  # pragma: no cover - Windows fallback
     fcntl = None  # type: ignore[assignment]
     import msvcrt
 
-from deerflow.config import get_app_config
+from deerflow.config.app_config import AppConfig
 from deerflow.config.paths import VIRTUAL_PATH_PREFIX, get_paths
 from deerflow.sandbox.sandbox import Sandbox
 from deerflow.sandbox.sandbox_provider import SandboxProvider
@@ -148,7 +148,7 @@ class AioSandboxProvider(SandboxProvider):
 
     def _load_config(self) -> dict:
         """Load sandbox configuration from app config."""
-        config = get_app_config()
+        config = AppConfig.current()
         sandbox_config = config.sandbox
 
         idle_timeout = getattr(sandbox_config, "idle_timeout", None)
@@ -279,7 +279,7 @@ class AioSandboxProvider(SandboxProvider):
         so the host Docker daemon can resolve the path.
         """
         try:
-            config = get_app_config()
+            config = AppConfig.current()
             skills_path = config.skills.get_skills_path()
             container_path = config.skills.container_path
 

backend/packages/harness/deerflow/community/ddg_search/tools.py

@@ -7,7 +7,7 @@ import logging
 
 from langchain.tools import tool
 
-from deerflow.config import get_app_config
+from deerflow.config.app_config import AppConfig
 
 logger = logging.getLogger(__name__)
 
@@ -63,7 +63,7 @@ def web_search_tool(
         query: Search keywords describing what you want to find. Be specific for better results.
         max_results: Maximum number of results to return. Default is 5.
     """
-    config = get_app_config().get_tool_config("web_search")
+    config = AppConfig.current().get_tool_config("web_search")
 
     # Override max_results from config if set
     if config is not None and "max_results" in config.model_extra:

backend/packages/harness/deerflow/community/exa/tools.py

@@ -3,11 +3,11 @@ import json
 from exa_py import Exa
 from langchain.tools import tool
 
-from deerflow.config import get_app_config
+from deerflow.config.app_config import AppConfig
 
 
 def _get_exa_client(tool_name: str = "web_search") -> Exa:
-    config = get_app_config().get_tool_config(tool_name)
+    config = AppConfig.current().get_tool_config(tool_name)
     api_key = None
     if config is not None and "api_key" in config.model_extra:
         api_key = config.model_extra.get("api_key")
@@ -22,7 +22,7 @@ def web_search_tool(query: str) -> str:
         query: The query to search for.
     """
     try:
-        config = get_app_config().get_tool_config("web_search")
+        config = AppConfig.current().get_tool_config("web_search")
         max_results = 5
         search_type = "auto"
         contents_max_characters = 1000

backend/packages/harness/deerflow/community/firecrawl/tools.py

@@ -3,11 +3,11 @@ import json
 from firecrawl import FirecrawlApp
 from langchain.tools import tool
 
-from deerflow.config import get_app_config
+from deerflow.config.app_config import AppConfig
 
 
 def _get_firecrawl_client(tool_name: str = "web_search") -> FirecrawlApp:
-    config = get_app_config().get_tool_config(tool_name)
+    config = AppConfig.current().get_tool_config(tool_name)
     api_key = None
     if config is not None and "api_key" in config.model_extra:
         api_key = config.model_extra.get("api_key")
@@ -22,7 +22,7 @@ def web_search_tool(query: str) -> str:
         query: The query to search for.
     """
     try:
-        config = get_app_config().get_tool_config("web_search")
+        config = AppConfig.current().get_tool_config("web_search")
         max_results = 5
         if config is not None:
             max_results = config.model_extra.get("max_results", max_results)

backend/packages/harness/deerflow/community/image_search/tools.py

@@ -7,7 +7,7 @@ import logging
 
 from langchain.tools import tool
 
-from deerflow.config import get_app_config
+from deerflow.config.app_config import AppConfig
 
 logger = logging.getLogger(__name__)
 
@@ -99,7 +99,7 @@ def image_search_tool(
         type_image: Image type filter. Options: "photo", "clipart", "gif", "transparent", "line". Use "photo" for realistic references.
         layout: Layout filter. Options: "Square", "Tall", "Wide". Choose based on your generation needs.
     """
-    config = get_app_config().get_tool_config("image_search")
+    config = AppConfig.current().get_tool_config("image_search")
 
     # Override max_results from config if set
     if config is not None and "max_results" in config.model_extra:

backend/packages/harness/deerflow/community/infoquest/tools.py

@@ -1,6 +1,6 @@
 from langchain.tools import tool
 
-from deerflow.config import get_app_config
+from deerflow.config.app_config import AppConfig
 from deerflow.utils.readability import ReadabilityExtractor
 
 from .infoquest_client import InfoQuestClient
@@ -9,12 +9,12 @@ readability_extractor = ReadabilityExtractor()
 
 
 def _get_infoquest_client() -> InfoQuestClient:
-    search_config = get_app_config().get_tool_config("web_search")
+    search_config = AppConfig.current().get_tool_config("web_search")
     search_time_range = -1
     if search_config is not None and "search_time_range" in search_config.model_extra:
         search_time_range = search_config.model_extra.get("search_time_range")
 
-    fetch_config = get_app_config().get_tool_config("web_fetch")
+    fetch_config = AppConfig.current().get_tool_config("web_fetch")
     fetch_time = -1
     if fetch_config is not None and "fetch_time" in fetch_config.model_extra:
         fetch_time = fetch_config.model_extra.get("fetch_time")
@@ -25,7 +25,7 @@ def _get_infoquest_client() -> InfoQuestClient:
     if fetch_config is not None and "navigation_timeout" in fetch_config.model_extra:
         navigation_timeout = fetch_config.model_extra.get("navigation_timeout")
 
-    image_search_config = get_app_config().get_tool_config("image_search")
+    image_search_config = AppConfig.current().get_tool_config("image_search")
     image_search_time_range = -1
     if image_search_config is not None and "image_search_time_range" in image_search_config.model_extra:
         image_search_time_range = image_search_config.model_extra.get("image_search_time_range")

backend/packages/harness/deerflow/community/jina_ai/tools.py

@@ -1,7 +1,7 @@
 from langchain.tools import tool
 
 from deerflow.community.jina_ai.jina_client import JinaClient
-from deerflow.config import get_app_config
+from deerflow.config.app_config import AppConfig
 from deerflow.utils.readability import ReadabilityExtractor
 
 readability_extractor = ReadabilityExtractor()
@@ -20,7 +20,7 @@ async def web_fetch_tool(url: str) -> str:
     """
     jina_client = JinaClient()
     timeout = 10
-    config = get_app_config().get_tool_config("web_fetch")
+    config = AppConfig.current().get_tool_config("web_fetch")
     if config is not None and "timeout" in config.model_extra:
         timeout = config.model_extra.get("timeout")
     html_content = await jina_client.crawl(url, return_format="html", timeout=timeout)

backend/packages/harness/deerflow/community/tavily/tools.py

@@ -3,11 +3,11 @@ import json
 from langchain.tools import tool
 from tavily import TavilyClient
 
-from deerflow.config import get_app_config
+from deerflow.config.app_config import AppConfig
 
 
 def _get_tavily_client() -> TavilyClient:
-    config = get_app_config().get_tool_config("web_search")
+    config = AppConfig.current().get_tool_config("web_search")
     api_key = None
     if config is not None and "api_key" in config.model_extra:
         api_key = config.model_extra.get("api_key")
@@ -21,7 +21,7 @@ def web_search_tool(query: str) -> str:
     Args:
         query: The query to search for.
     """
-    config = get_app_config().get_tool_config("web_search")
+    config = AppConfig.current().get_tool_config("web_search")
     max_results = 5
     if config is not None and "max_results" in config.model_extra:
         max_results = config.model_extra.get("max_results")