[AZ-270] [AZ-272] [AZ-279] [AZ-281] [AZ-283] Compose root + FDR schema + 3 Layer-1 helpers

AZ-270: composition root with strategy registry, tier-gated lookup,
topo-order construction, all-or-nothing teardown, StrategyNotLinkedError
payload.
AZ-272: orjson-backed FdrRecord serialise/parse with forward-compat for
unknown payload + top-level fields and canonical overrun-record shape.
AZ-279: pyproj-backed WGS84/ECEF/ENU + OSM slippy-map tile math with
WgsConversionError for shape/range/zoom guards.
AZ-281: strict EngineFilenameSchema build/parse/matches_host with
anchored regex + enum validation; round-trip identity by construction.
AZ-283: dtype-preserving (fp16/fp32) single + batch L2 normaliser with
zero-norm safety and descriptor_metric() source-of-truth.
pyproject.toml pins pyproj>=3.6 and orjson>=3.9 (named-backend deps per
the AZ-272 / AZ-279 contracts). New DTOs LatLonAlt + BoundingBox and
EngineCacheKey + HostCapabilities land in _types/ to back the helper
contracts.
203 unit tests pass (64 new). Review verdict: PASS_WITH_WARNINGS;
findings are perf-NFR deferrals + dep amendment + minor docstring polish.

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

src/gps_denied_onboard/fdr_client/__init__.py

@@ -5,6 +5,27 @@ Producer-side API used by every component. Consumer-side writer lives in
 """
 
 from gps_denied_onboard.fdr_client.client import FdrClient
-from gps_denied_onboard.fdr_client.records import FdrRecord
+from gps_denied_onboard.fdr_client.records import (
+    CURRENT_SCHEMA_VERSION,
+    KNOWN_KINDS,
+    MAX_INLINE_BLOB_BYTES,
+    OVERRUN_KIND,
+    OVERRUN_PRODUCER_ID,
+    FdrRecord,
+    FdrSchemaError,
+    parse,
+    serialise,
+)
 
-__all__ = ["FdrClient", "FdrRecord"]
+__all__ = [
+    "CURRENT_SCHEMA_VERSION",
+    "KNOWN_KINDS",
+    "MAX_INLINE_BLOB_BYTES",
+    "OVERRUN_KIND",
+    "OVERRUN_PRODUCER_ID",
+    "FdrClient",
+    "FdrRecord",
+    "FdrSchemaError",
+    "parse",
+    "serialise",
+]