feat(runner): 注入 tool_dispatch_factory/prompt_builder_factory + fail-fast

Runner.__init__ 新增 2 个可选参数:
- tool_dispatch_factory: 工具调度工厂
- prompt_builder_factory: prompt 构建工厂

infer/eval/train 模式缺少工厂时 fail-fast 抛 ValueError。
_make_tool_dispatch_fn/_make_prompt_builder 优先使用注入工厂。

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

app/harness/runner.py

@@ -449,6 +449,8 @@ class Runner:
         evolve_llm: 进化用 LLMProvider（thinking=True）。
         vlm: VLMProvider。
         telemetry: 遥测记录端口。
+        tool_dispatch_factory: 工具调度工厂（infer/eval/train 模式必传）。
+        prompt_builder_factory: prompt 构建工厂（infer/eval/train 模式必传）。
     """
 
     def __init__(
@@ -459,12 +461,28 @@ class Runner:
         evolve_llm: LLMProvider,
         vlm: VLMProvider,
         telemetry: TelemetryRecorder,
+        tool_dispatch_factory: Any | None = None,
+        prompt_builder_factory: Any | None = None,
     ) -> None:
         self._config = config
         self._llm = llm
         self._evolve_llm = evolve_llm
         self._vlm = vlm
         self._telemetry = telemetry
+        self._tool_dispatch_factory = tool_dispatch_factory
+        self._prompt_builder_factory = prompt_builder_factory
+
+        # fail-fast: 需要推理的模式必须注入工厂
+        if config.mode in {"infer", "eval", "train"} and (
+            tool_dispatch_factory is None or prompt_builder_factory is None
+        ):
+            raise ValueError(
+                f"mode={config.mode!r} 需要 tool_dispatch_factory 和 "
+                f"prompt_builder_factory，但收到 "
+                f"tool_dispatch_factory={tool_dispatch_factory!r}, "
+                f"prompt_builder_factory={prompt_builder_factory!r}"
+            )
+
         self._ensure_workspace()
         self._paths: ResolvedPaths = resolve_paths(config.workspace_dir)
 
@@ -2062,22 +2080,26 @@ class Runner:
     # -----------------------------------------------------------------------
 
     def _make_tool_dispatch_fn(self, *, skills_dir: Path | None = None):
-        """构造工具调度函数（由子类或 main.py 覆盖）。"""
+        """构造工具调度函数（优先使用注入的工厂，否则 noop 降级）。"""
+        if self._tool_dispatch_factory is not None:
+            return self._tool_dispatch_factory(skills_dir=skills_dir)
 
+        # noop fallback：diagnose/promote 等不需要推理的模式
         async def _noop_dispatch(tool_name: str, args: dict, *, context: dict) -> str:
-            raise NotImplementedError(
-                f"工具 {tool_name} 调度未配置（需由 main.py 注入 tool_dispatch_fn）"
-            )
+            raise NotImplementedError(f"工具 {tool_name} 调度未配置")
 
         return _noop_dispatch
 
     def _make_prompt_builder(
         self, *, skills_dir: Path | None = None, prompts_dir: Path | None = None
     ):
-        """构造 prompt 构建函数（由子类或 main.py 覆盖）。"""
+        """构造 prompt 构建函数（优先使用注入的工厂，否则 noop 降级）。"""
+        if self._prompt_builder_factory is not None:
+            return self._prompt_builder_factory(skills_dir=skills_dir, prompts_dir=prompts_dir)
 
+        # noop fallback：diagnose/promote 等不需要推理的模式
         def _noop_builder(qa: GeneratedQuestion) -> tuple[str, str]:
-            raise NotImplementedError("prompt_builder 未配置（需由 main.py 注入）")
+            raise NotImplementedError("prompt_builder 未配置")
 
         return _noop_builder