[AZ-263] Bootstrap: repo skeleton + Docker + CI + Alembic + Tier-1 tests

Implements the AZ-263 / E-BOOT initial structure task:

- Python src/-layout package `gps_denied_onboard/` with per-component
  interface stubs (14 components), type-only DTOs under `_types/`,
  shared helpers under `helpers/` (R14 LightGlue ownership), structured
  JSON logging, runtime composition root with env-var fail-fast gate,
  healthcheck module shared by Docker and CI smoke.
- CMake top-level + `cmake/{build_options,dependencies,strategies}.cmake`
  with the BUILD_* per-binary flags (ADR-002) and pinned external git
  refs for OKVIS2 / VINS-Mono / GTSAM / FAISS / OpenCV >=4.12.0.
- Three Dockerfiles (companion-tier1, operator-tooling,
  mock-suite-sat-service) + two compose files (dev + Tier-1 test).
- Four GitHub Actions workflows: ci.yml (lint/unit/integration/dual
  binary build/SBOM diff/security), ci-tier2.yml (self-hosted Jetson
  AC-bound NFTs), release.yml, cve-rescan.yml.
- Two CI gate scripts: `ci/sbom_diff.py` (deployment SBOM subset +
  R02 exclusion), `ci/opencv_pin_gate.py` (>=4.12.0 enforcement,
  D-CROSS-CVE-1).
- Alembic-driven Postgres 16 initial migration `0001_initial.py`
  mirroring satellite-provider tiles + flights + sector_classifications
  + manifests + engine_cache_entries (data_model.md s 2).
- Tier-1 test scaffolding: 95 passing unit tests covering every AC,
  per-component smoke tests, structured logging JSON output check,
  env-var gate check, healthcheck import check. Two CI-gated tests
  (cmake configure, actionlint) skip locally with explicit reasons.
- Batch report + code review report under `_docs/03_implementation/`.

Verdict: PASS_WITH_WARNINGS (two Low findings, both informational).
Co-authored-by: Cursor <cursoragent@cursor.com>

src/gps_denied_onboard/helpers/wgs_converter.py

@@ -0,0 +1,26 @@
+"""WGS84 ↔ local-tangent-plane converter — STUB.
+
+Concrete implementation is owned by AZ-279. Contract:
+`_docs/02_document/common-helpers/04_helper_wgs_converter.md`.
+"""
+
+from __future__ import annotations
+
+
+def wgs84_to_ltp(
+    lat_deg: float,
+    lon_deg: float,
+    alt_m: float,
+    ref_lat_deg: float,
+    ref_lon_deg: float,
+    ref_alt_m: float,
+) -> tuple[float, float, float]:
+    """Convert a WGS-84 lat/lon/alt to local-tangent-plane east/north/up metres."""
+    raise NotImplementedError("wgs_converter concrete impl is AZ-279")
+
+
+def ltp_to_wgs84(
+    e_m: float, n_m: float, u_m: float, ref_lat_deg: float, ref_lon_deg: float, ref_alt_m: float
+) -> tuple[float, float, float]:
+    """Inverse of wgs84_to_ltp."""
+    raise NotImplementedError("wgs_converter concrete impl is AZ-279")