[AZ-699] Real-flight validation runner + Markdown accuracy report

New e2e test runs gps-denied-replay --auto-trim against the real
derkachi.tlog + flight video + AZ-702 calibration, computes the
horizontal-error distribution (mean/p50/p95/p99 + 10/25/50/100 m
threshold-hit share), writes _docs/06_metrics/real_flight_
validation_{date}.md, and asserts honest PASS/FAIL with no @xfail
mask. AZ-404's 1-min test is untouched (sibling, not replacement).

Extends gps_compare.py with HorizontalErrorDistribution +
percentile_sorted (numpy-equivalent linear interpolation). New
test helper _report_writer.py renders the canonical Markdown
schema documented as FT-P-20 in blackbox-tests.md.

16 new unit tests pin distribution arithmetic, verdict gate,
failure-message templating (references calibration acquisition
method per AC-3), and report layout. 129 passed in focused
regression, 3 skipped (real video / Tier-2 prerequisites).
Zero new mypy --strict errors.

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

_docs/_autodev_state.md

@@ -8,8 +8,8 @@ status: in_progress
 sub_step:
   phase: 6
   name: implement-tasks-sequentially
-  detail: "batch 100 of ~102: AZ-699"
+  detail: "batch 101 of ~102: AZ-700"
 retry_count: 0
 cycle: 2
 tracker: jira
-last_completed_batch: 99
+last_completed_batch: 100