[AZ-332] C1 OKVIS2 Strategy: facade + binding skeleton

Python facade (`Okvis2Strategy`) is production-quality and satisfies
AZ-331's `VioStrategy` protocol; full AC-1..10 coverage with
AC-9 + NFR-perf marked `tier2`. The C++ pybind11 binding compiles
and loads but throws `OkvisFatalException("estimator not yet wired")`
on first `add_frame` — the `okvis::ThreadedKFVio` wiring is a tier2
follow-up the Step-15 Product Completeness Gate is expected to track
as a remediation task.

Resolved contradictions:

* Constructor signature aligned with the AZ-331 factory: `(config, *,
  fdr_client, clock=None)`. Calibration / preintegrator / logger
  built internally from config. No churn on AZ-331.
* IMU substrate: OKVIS2 owns its internal estimator IMU integration;
  the AZ-276 `ImuPreintegrator` is a separate substrate consumed by
  E-C5's fusion graph. Single source of truth lives at the sample
  stream, not the integrator instance.
* FDR API: `FdrClient.enqueue(record)` with new `vio.health` kind
  added to AZ-272 `KNOWN_PAYLOAD_KEYS`.

CI matrix forces `-DBUILD_OKVIS2=OFF` until the tier2 wiring task
brings Ceres / SuiteSparse / OKVIS2 vendored submodules into the
Linux build.

Files: 17 added/modified across `c1_vio/`, `fdr_client/records.py`,
`cpp/okvis2/CMakeLists.txt`, CI workflow, AZ-332 task spec
(implementation-notes section), batch 23 report.

Tests: 17 new (15 tier1 + 2 tier2). Full Tier-1 suite: 1109 pass,
2 skipped (env), 2 deselected (tier2). No regressions.

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

tests/unit/c1_vio/test_protocol_conformance.py

@@ -40,7 +40,6 @@ from gps_denied_onboard.config.schema import Config, ConfigError
 from gps_denied_onboard.runtime_root.errors import StrategyNotAvailableError
 from gps_denied_onboard.runtime_root.vio_factory import build_vio_strategy
 
-
 _CONTRACT_PATH = (
     Path(__file__).resolve().parents[3]
     / "_docs/02_document/contracts/c1_vio/vio_strategy_protocol.md"
@@ -250,6 +249,16 @@ def test_ac5_build_vio_strategy_flag_off_no_import(
     assert module_name not in sys.modules
 
 
+# Which strategies still have NO concrete Python module on disk?
+# Once an AZ-332 / AZ-333 / AZ-334 implementation lands, the
+# `flag_on_but_module_missing` semantic shifts: the factory's import
+# succeeds, the constructor fails on missing native binding or other
+# prerequisite. We assert the meaningful-error-before-first-frame
+# property holds for BOTH cases — the exception class differs by
+# strategy.
+_STRATEGIES_WITHOUT_PY_MODULE: tuple[str, ...] = ("vins_mono", "klt_ransac")
+
+
 @pytest.mark.parametrize("strategy", sorted(_STRATEGY_MODULES))
 def test_ac5_build_vio_strategy_flag_on_but_module_missing(
     monkeypatch, strategy_module_cleanup, strategy
@@ -257,9 +266,20 @@ def test_ac5_build_vio_strategy_flag_on_but_module_missing(
     _, _, flag = _STRATEGY_MODULES[strategy]
     monkeypatch.setenv(flag, "ON")
     config = _config_with_strategy(strategy)
-    with pytest.raises(StrategyNotAvailableError) as exc_info:
-        build_vio_strategy(config, fdr_client=object())
-    assert strategy in str(exc_info.value)
+    if strategy in _STRATEGIES_WITHOUT_PY_MODULE:
+        # Module not yet implemented — factory's __import__ raises
+        # ModuleNotFoundError, rewrapped into StrategyNotAvailableError.
+        with pytest.raises(StrategyNotAvailableError) as exc_info:
+            build_vio_strategy(config, fdr_client=object())
+        assert strategy in str(exc_info.value)
+    else:
+        # Module IS implemented (AZ-332). Factory import succeeds, then
+        # the strategy constructor fails on missing native binding —
+        # which the strategy MUST surface as VioFatalError BEFORE any
+        # frame is processed (the AC-5 spirit: no silent fall-through).
+        with pytest.raises(VioFatalError) as exc_info:
+            build_vio_strategy(config, fdr_client=object())
+        assert "native binding" in str(exc_info.value)
 
 
 # ----------------------------------------------------------------------
@@ -292,9 +312,7 @@ def test_ac7_current_strategy_label_matches_config(
     config = _config_with_strategy(strategy)
     instance = build_vio_strategy(config, fdr_client=object())
     assert instance.current_strategy_label() == strategy
-    assert (
-        instance.current_strategy_label() == config.components["c1_vio"].strategy
-    )
+    assert instance.current_strategy_label() == config.components["c1_vio"].strategy
 
 
 # ----------------------------------------------------------------------
@@ -314,9 +332,7 @@ def _methods_from_contract() -> set[str]:
 
 def _protocol_methods(proto: type) -> set[str]:
     return {
-        name
-        for name in dir(proto)
-        if not name.startswith("_") and callable(getattr(proto, name))
+        name for name in dir(proto) if not name.startswith("_") and callable(getattr(proto, name))
     }
 
 
@@ -338,9 +354,7 @@ def test_ac8_contract_methods_match_protocol() -> None:
 def test_ac8_contract_lists_all_three_error_subtypes() -> None:
     text = _CONTRACT_PATH.read_text(encoding="utf-8")
     for name in {"VioInitializingError", "VioDegradedError", "VioFatalError"}:
-        assert name in text, (
-            f"Contract file is missing the documented error subtype {name!r}"
-        )
+        assert name in text, f"Contract file is missing the documented error subtype {name!r}"
 
 
 # ----------------------------------------------------------------------
@@ -358,9 +372,7 @@ def test_ac9_vio_output_frame_id_is_typed_str() -> None:
     :class:`SE3`).
     """
     annotation = VioOutput.__annotations__["frame_id"]
-    assert annotation == "str", (
-        f"frame_id annotation should be 'str'; got {annotation!r}"
-    )
+    assert annotation == "str", f"frame_id annotation should be 'str'; got {annotation!r}"
 
 
 def test_ac9_vio_output_docstring_documents_echo_invariant() -> None:
@@ -388,9 +400,7 @@ def test_nfr_reliability_strategy_not_available_not_in_family() -> None:
     assert not issubclass(StrategyNotAvailableError, VioError)
 
 
-def test_nfr_perf_factory_under_200ms_p99(
-    monkeypatch, strategy_module_cleanup
-) -> None:
+def test_nfr_perf_factory_under_200ms_p99(monkeypatch, strategy_module_cleanup) -> None:
     """Factory p99 ≤ 200 ms across 1000 calls (NFR-perf-factory)."""
     strategy = "klt_ransac"
     _, _, flag = _STRATEGY_MODULES[strategy]
@@ -406,9 +416,7 @@ def test_nfr_perf_factory_under_200ms_p99(
 
     durations_ms.sort()
     p99 = durations_ms[int(0.99 * len(durations_ms))]
-    assert p99 <= 200.0, (
-        f"build_vio_strategy() p99={p99:.3f} ms exceeds 200 ms NFR"
-    )
+    assert p99 <= 200.0, f"build_vio_strategy() p99={p99:.3f} ms exceeds 200 ms NFR"
 
 
 # ----------------------------------------------------------------------