[AZ-266] [AZ-269] [AZ-277] [AZ-280] Cross-cutting log/config + SE3/SHA256 helpers

AZ-266: schema-compliant JSON logging entrypoint, level normalisation,
handler-topology guard, format-error fallback (log_record_schema v1.0.0).
AZ-269: env > YAML > defaults config loader, frozen Config dataclass,
missing-var fail-fast with pointer to .env.example, component-block registry.
AZ-277: GTSAM-backed SE3Utils (matrix<->SE3 + exp/log/adjoint) with strict
orthogonality, dtype, and bottom-row contract enforcement.
AZ-280: atomicwrites-backed write_atomic + independent verify +
order-deterministic aggregate_hash; sidecar format strictness.
pyproject.toml pins gtsam>=4.2,<5.0 and atomicwrites>=1.4,<2.0
(named-backend deps per the AZ-277 / AZ-280 contracts).
139 unit tests pass (44 new). Review verdict: PASS_WITH_WARNINGS;
findings are perf-NFR + journald deferrals, no blocking issues.

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

tests/unit/test_logging_smoke.py

@@ -1,9 +1,11 @@
-"""Structured logging smoke — AZ-263 AC-7."""
+"""Structured logging smoke — AZ-263 AC-7 (schema-compliant per AZ-266)."""
 
+import io
 import json
 import logging
 
 from gps_denied_onboard.logging import get_logger
+from gps_denied_onboard.logging.structured import JsonFormatter
 
 
 def test_get_logger_returns_logger_instance() -> None:
@@ -16,25 +18,24 @@ def test_get_logger_returns_logger_instance() -> None:
 
 def test_log_lines_are_single_json_objects() -> None:
     # Arrange
-    import io
-
-    from gps_denied_onboard.logging.structured import _JsonFormatter
-
     stream = io.StringIO()
     handler = logging.StreamHandler(stream)
-    handler.setFormatter(_JsonFormatter())
+    handler.setFormatter(JsonFormatter())
     logger = logging.getLogger("test.json.unit")
     logger.handlers = [handler]
     logger.setLevel(logging.DEBUG)
     logger.propagate = False
 
     # Act
-    logger.error("hello world", extra={"event": "smoke", "value": 42})
+    logger.error(
+        "hello world",
+        extra={"kind": "test.smoke", "kv": {"event": "smoke", "value": 42}},
+    )
 
     # Assert
     line = stream.getvalue().strip().splitlines()[-1]
     payload = json.loads(line)
     assert payload["level"] == "ERROR"
     assert payload["msg"] == "hello world"
-    assert payload["event"] == "smoke"
-    assert payload["value"] == 42
+    assert payload["kind"] == "test.smoke"
+    assert payload["kv"] == {"event": "smoke", "value": 42}