[AZ-297] C7 InferenceRuntime: Protocol + DTOs + factory

Freezes the c7_inference Public API per
_docs/02_document/contracts/c7_inference/inference_runtime_protocol.md
v1.0.0:

- InferenceRuntime Protocol (6 methods: compile_engine,
  deserialize_engine, infer, release_engine, thermal_state,
  current_runtime_label) in components/c7_inference/interface.py.
- DTOs (PrecisionMode enum, OptimizationProfile, BuildConfig,
  EngineCacheEntry, EngineHandle opaque marker) in _types/inference.py
  — placed at the L1 types layer so C10 can re-export EngineCacheEntry
  without crossing the components.* boundary (AZ-270 AC-6).
- ThermalState DTO expanded in _types/thermal.py from the AZ-355
  forward-declared stub to the AZ-297 contract shape (cpu/gpu temp,
  thermal_throttle_active, measured_clock_mhz, measured_at_ns,
  is_telemetry_available). Invariant I-6: when telemetry is
  unavailable, throttle is False.
- Error family rooted at c7_inference.errors.RuntimeError (9 subtypes:
  EngineBuildError, EngineDeserializeError, EngineHashMismatchError,
  EngineSchemaMismatchError, EngineSidecarMissingError,
  CalibrationCacheError, InferenceError, OutOfMemoryError,
  TelemetryUnavailableError). RuntimeNotAvailableError stays in
  runtime_root/errors.py — composition-time, outside the family.
- C7InferenceConfig per-component config block (runtime label,
  thermal_poll_hz, engine_cache_dir) with constructor-time validation
  rejecting unknown runtime labels.
- Composition-root factory build_inference_runtime in
  runtime_root/inference_factory.py with three BUILD_* gates
  (BUILD_TENSORRT_RUNTIME, BUILD_ONNX_TRT_EP_RUNTIME,
  BUILD_PYTORCH_FP16_RUNTIME). Concrete strategy modules are imported
  lazily via __import__ AFTER the flag check, so a Tier-0 build with
  the flag OFF MUST NOT load the strategy module (AC-5 / I-5;
  verifiable via sys.modules).
- 37 conformance tests cover all 8 ACs + NFR-perf-factory
  (p99 build under 200 ms × 1000 calls) + NFR-reliability-error-family.
  AC-8 introspects the contract file's Shape table and asserts method
  parity against the runtime Protocol; also asserts all 9 error
  subtypes are documented.

Retired the AZ-263 scaffolding EngineCacheEntry from _types/manifests.py
(replaced by the AZ-297 canonical shape in _types/inference.py); updated
the LightGlue-flavoured EngineHandle Protocol docstring in
_types/manifests.py to rationalize its intentional dual existence
with the C7 opaque EngineHandle (same name, different consumer-side
cut, mirroring the C4/C5 ISam2GraphHandle pattern).

Stale ThermalState.throttle docstring references in c4_pose/config.py,
c4_pose/interface.py, and _types/pose.py updated to
thermal_throttle_active.

Full unit-test sweep: 843 passed, 2 pre-existing environment skips
(cmake, actionlint).

Co-authored-by: Cursor <cursoragent@cursor.com>

src/gps_denied_onboard/components/c7_inference/config.py

@@ -0,0 +1,63 @@
+"""C7 inference runtime config block (AZ-297).
+
+Registered into ``config.components['c7_inference']`` by the package
+``__init__.py``. The composition-root factory
+:func:`gps_denied_onboard.runtime_root.inference_factory.build_inference_runtime`
+reads this block to select the strategy and locate the engine cache.
+"""
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+from typing import Final
+
+from gps_denied_onboard.config.schema import ConfigError
+
+__all__ = [
+    "C7InferenceConfig",
+    "KNOWN_RUNTIMES",
+]
+
+KNOWN_RUNTIMES: Final[frozenset[str]] = frozenset(
+    {"tensorrt", "onnx_trt_ep", "pytorch_fp16"}
+)
+
+
+@dataclass(frozen=True)
+class C7InferenceConfig:
+    """Per-component config for C7 inference.
+
+    ``runtime`` selects exactly one of the three strategies
+    (``tensorrt`` / ``onnx_trt_ep`` / ``pytorch_fp16``); the
+    composition-root factory respects compile-time ``BUILD_*`` gating
+    on top of this label (a runtime whose flag is OFF raises
+    :class:`RuntimeNotAvailableError` at composition time).
+
+    ``thermal_poll_hz`` is the cadence at which AZ-302's
+    ``ThermalStatePublisher`` polls ``tegrastats`` / ``jtop``;
+    default 1 Hz keeps the SDK telemetry source cool.
+
+    ``engine_cache_dir`` is the filesystem root where compiled
+    ``.engine`` binaries + ``.sha256`` sidecars live; the C10
+    pre-flight ``CacheProvisioner`` writes here.
+    """
+
+    runtime: str = "pytorch_fp16"
+    thermal_poll_hz: float = 1.0
+    engine_cache_dir: str = "/var/lib/gps-denied/engines"
+
+    def __post_init__(self) -> None:
+        if self.runtime not in KNOWN_RUNTIMES:
+            raise ConfigError(
+                f"C7InferenceConfig.runtime={self.runtime!r} not in "
+                f"{sorted(KNOWN_RUNTIMES)}"
+            )
+        if self.thermal_poll_hz <= 0:
+            raise ConfigError(
+                f"C7InferenceConfig.thermal_poll_hz must be > 0; "
+                f"got {self.thermal_poll_hz}"
+            )
+        if not self.engine_cache_dir:
+            raise ConfigError(
+                "C7InferenceConfig.engine_cache_dir must be non-empty"
+            )