[AZ-381] Fix ISam2GraphHandleImpl missing get_pose_key + comments

F1 (High/Architecture) from cumulative review of batches 01-22:
`ISam2GraphHandleImpl` did not satisfy C4's `ISam2GraphHandle`
Protocol stub (AZ-355) because it lacked `get_pose_key`.
`pose_factory`'s isinstance gate would have raised at composition.
Two Protocols (C4 minimal consumer cut, C5 richer producer surface)
are intentional per AZ-355 Risk 1 — the impl just needed to expose
the canonical name. Delegates to estimator.key_for_frame.

Added cross-component conformance test asserting the C5 impl
satisfies both Protocols, so future drift trips a unit test.

F2 (Medium/Maintainability): added justifying comments at four
`except: pass` sites in runtime_root, c8_fc_adapter (ap + inav),
and c13_fdr writer. No behavioral change.

Updated cumulative review report verdict from FAIL to PASS and
recorded a post-mortem on the initial misframing
(treated the dual-Protocol design as duplication on first read).

Autodev state: batch 22 done, cumulative-review PASS,
ready for batch 23.

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

src/gps_denied_onboard/runtime_root/__init__.py

@@ -543,6 +543,9 @@ def _abort_takeoff_on_fdr_open_error(
                 },
             )
         except Exception:
+            # Even the error-logging failed during abort; we still have the
+            # stderr print below to surface the original failure to the
+            # operator. Swallowing keeps the abort path single-exit.
             pass
     print(
         f"FATAL: cannot open FDR at {resolved_root}: {underlying}; aborting takeoff (exit 2)",