[AZ-961] accuracy_report: rename tlog_path -> ground_truth_path

ReportContext.tlog_path was widened in-place by AZ-959 to mean
"ground-truth source path" without renaming, leaving the rendered
report's "- Tlog: <csv_path>" line cosmetically wrong for CSV
runs. This rename + label fix completes the cleanup.

- helpers/accuracy_report.py: field rename + docstring update +
  rendered line now reads "- Ground truth: <path>" for both
  inputs.
- replay_api/app.py: kwarg updated, AZ-959 inline comment about
  the overload removed (field name now carries the intent).
- tests/unit/test_az699_report_writer.py: fixture updated, two
  new symmetric tests assert the canonical label for tlog AND
  csv inputs (AC-2).
- tests/e2e/replay/_e2e_orchestrator.py +
  test_derkachi_real_tlog.py: kwarg updated.

Tests: 62/62 green across test_az699_report_writer.py,
test_az700_render_map.py, test_az701_replay_api.py.

CSV-replay-input chain (AZ-959 + AZ-960 + AZ-961) is now coherent:
- API accepts (video, csv) with XOR validation
- /static/example-csv serves the AZ-896 reference doc
- Runner dispatches --imu vs --tlog argv
- Report renders with source-agnostic "Ground truth:" label
- Map renders from CSV truth via gps-denied-render-map dispatch

Bookkeeping: AZ-961 spec moved todo/ → done/, dep-table preamble
eighth bump documents the rename + summarises the cycle-4 CSV
chain, state.md records batch 7 complete.

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

src/gps_denied_onboard/replay_api/app.py

@@ -237,11 +237,7 @@ class SubprocessReplayRunner:
         )
         context = ReportContext(
             run_date_utc=datetime.utcnow().date().isoformat(),
-            # tlog_path is widened to "ground-truth source" in cycle-4
-            # (tlog or csv depending on which input drove the run);
-            # ReportContext field rename deferred to AZ-699 follow-up
-            # to keep AZ-959 scope minimal.
-            tlog_path=gt_source_path,
+            ground_truth_path=gt_source_path,
             video_path=inputs.video_path,
             calibration_acquisition_method=calibration_method,
             clip_duration_s=clip_duration_s,