feat: add OcrSettings scope configuration

src/polygateway/config.py

@@ -407,3 +407,29 @@ class EmbeddingSettings:
             normalize=bool(_cast(norm[1], "bool", norm[0])) if norm else False,
             expected_dim=expected_dim,
         )
+
+
+@dataclass(frozen=True)
+class OcrSettings:
+    """OCR scope 装配配置(M3 设计 §3.4): 复用 GatewaySettings,无 OCR 专用键。
+
+    cache/structured/pricing 键对 OCR 无意义,装配时忽略;TPM 闸不启用
+    (tpm=0)、看门狗键不配(非流式)由源键缺省自然达成。api_key 惯例填
+    "none"(MonkeyOCR 无鉴权,SourceConfig 非空校验用占位)。
+    """
+
+    gateway: GatewaySettings
+
+    @classmethod
+    def from_env(
+        cls,
+        scope: str = "OCR",
+        env: Mapping[str, str] | None = None,
+        *,
+        env_file: str = ".env",
+    ) -> OcrSettings:
+        if env is None:
+            env = {
+                k: v for k, v in {**dotenv_values(env_file), **os.environ}.items() if v is not None
+            }
+        return cls(gateway=GatewaySettings.from_env(scope.upper(), env=env))

tests/unit/test_config.py

@@ -274,3 +274,48 @@ class TestAssemblyGuards:
         env_ok = dict(env)
         env_ok["LLM__BACKPRESSURE__STALL_WINDOW_S"] = "60"
         assert GatewaySettings.from_env("LLM", env=env_ok).backpressure.stall_window_s == 60.0
+
+
+class TestOcrSettings:
+    """M3 OcrSettings(设计 §3.4): 复用 GatewaySettings,无 OCR 专用键。"""
+
+    _OCR_ENV = {
+        "OCR__MONKEY__1__BASE_URL": "http://10.77.0.20:7866",
+        "OCR__MONKEY__1__API_KEY": "none",  # 无鉴权占位惯例
+        "OCR__MONKEY__1__MODEL": "monkey-ocr",
+        "OCR__MONKEY__1__TIMEOUT_S": "120",
+        "LLM_MAX_RETRIES": "3",
+        "LLM_RETRY_BASE_DELAY": "2.0",
+        "LLM_RETRY_MAX_DELAY": "30.0",
+        "LLM_CIRCUIT_BREAKER_THRESHOLD": "5",
+        "LLM_CIRCUIT_BREAKER_COOLDOWN": "60",
+        "PGW_CACHE_BACKEND": "none",
+        "PGW_TELEMETRY_BACKEND": "none",
+    }
+
+    def test_minimal_ocr_scope(self):
+        from polygateway.config import OcrSettings
+
+        settings = OcrSettings.from_env("OCR", env=dict(self._OCR_ENV))
+        gw = settings.gateway
+        assert gw.scope == "ocr"  # GatewaySettings 统一小写归一(既有约定)
+        assert gw.sources[0].name == "monkey_1"
+        assert gw.sources[0].provider == "monkey"
+        assert gw.sources[0].trust_env is True
+
+    def test_scope_resilience_override(self):
+        from polygateway.config import OcrSettings
+
+        env = dict(self._OCR_ENV)
+        env["OCR__RETRY__MAX_ATTEMPTS"] = "5"
+        env["OCR__MONKEY__1__TRUST_ENV"] = "false"
+        settings = OcrSettings.from_env("OCR", env=env)
+        assert settings.gateway.retry.max_attempts == 5
+        assert settings.gateway.sources[0].trust_env is False
+
+    def test_missing_base_url_fails(self):
+        from polygateway.config import OcrSettings
+
+        env = {k: v for k, v in self._OCR_ENV.items() if k != "OCR__MONKEY__1__BASE_URL"}
+        with pytest.raises(ValueError):
+            OcrSettings.from_env("OCR", env=env)