feat(harness): init ESKF from adapter's first GT pose as synthetic GPS origin

Wires a real CoordinateTransformer into the processor and seeds the ESKF
with the dataset's first ground-truth lat/lon/alt before the frame loop.
Result on EuRoC MH_01 (100 frames):
  eskf_initialized: 0/100 → 100/100
  vo_success: 99/100 (unchanged)
  eskf_has_position: 100/100

Satellite measurements are now correctly rejected by the Mahalanobis gate
(Δ² ~10⁶) because ORB produces unit-scale translations (scale_ambiguous=True)
which drive the ESKF position to diverge rapidly. The gate is working as
intended — the remaining issue is VO metric scale, not ESKF initialisation.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/e2e/test_euroc.py

@@ -38,9 +38,11 @@ async def test_euroc_mh01_rmse_within_ceiling(euroc_mh01_root: Path):
     result = await harness.run()
     if result.estimated_positions_enu.shape[0] == 0:
         pytest.xfail(
-            "Pipeline emits GPS estimates via fallback satellite matching but ESKF never "
-            "initialises (no start_gps call in harness). VO now engages at 99% with ORB. "
-            "Next: wire ESKF init with a synthetic GPS origin in the harness."
+            "Pipeline emits zero GPS estimates — ESKF+VO active (99/100 vo_success, "
+            "100/100 eskf_initialized) but satellite outlier rejection blocks all fixes. "
+            "Root cause: ORB scale_ambiguous=True → unit-scale VO translation → ESKF "
+            "position diverges → Mahalanobis gate rejects satellite measurements (~10^6 >> 16.3). "
+            "Next: apply VO scale from ESKF velocity or switch to metric VO backend."
         )
     # Align lengths by truncating to shorter (estimates may lag GT at start)
     n = min(result.estimated_positions_enu.shape[0], result.ground_truth.shape[0])
@@ -51,7 +53,8 @@ async def test_euroc_mh01_rmse_within_ceiling(euroc_mh01_root: Path):
     if ate["rmse"] >= EUROC_MH01_RMSE_CEILING_M:
         pytest.xfail(
             f"ATE RMSE={ate['rmse']:.2f}m exceeds {EUROC_MH01_RMSE_CEILING_M}m ceiling. "
-            "VO engages (99%) but ESKF never initialises without a start_gps call in the "
-            "harness — estimates come from satellite fallback only."
+            "VO+ESKF both active but ORB translation is unit-scale (scale_ambiguous=True) → "
+            "ESKF position diverges rapidly → satellite Mahalanobis gate rejects all fixes. "
+            "Fix: recover metric scale from ESKF velocity or use cuVSLAM (metric VO)."
         )
     assert ate["rmse"] < EUROC_MH01_RMSE_CEILING_M, f"ATE RMSE={ate['rmse']:.2f}m"