[AZ-334] C1 KLT/RANSAC strategy — engine-rule simple-baseline VIO

Implement KltRansacStrategy, the ADR-002 engine-rule mandatory
simple-baseline VioStrategy for E-C1. Pure-Python facade over
OpenCV's cv2.goodFeaturesToTrack / calcOpticalFlowPyrLK /
findEssentialMat / recoverPose pipeline — no C++/pybind11 binding
by design so a Tier-0 workstation runs the strategy with
`pip install opencv-python` and the BUILD_KLT_RANSAC=ON gate alone.
Constructor + state machine + FDR transition spine mirror
Okvis2Strategy + VinsMonoStrategy so the AZ-331 factory + IT-12
comparative harness treat all three as drop-in substitutable; the
duplication is the consolidation target now formally in scope for
the next cumulative review (batches 52-54).

AC coverage: AC-1..AC-11 + NFR-perf mapped to passing tests
(25 tests, 23 pass + 2 tier-2 skipped on dev/CI runners; all 25
pass under GPS_DENIED_TIER=2). Honest-covariance invariant (AC-9)
implemented as residual-scatter / (N_inliers - 5) with an inlier-
count penalty — no client-side floor or smoother; cov Frobenius
grows monotonically across DEGRADED. Camera-agnostic source
(AC-11) enforced by CI-grep gate that excludes docstring text.

Test-Run Cadence: focused suite tests/unit/c1_vio/ green (95 passed,
6 skipped); config-loader + compose-root suites green; full-suite
gate deferred to Step 16 per implement skill.

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

_docs/_autodev_state.md

@@ -12,5 +12,6 @@ sub_step:
 retry_count: 0
 cycle: 1
 tracker: jira
-last_completed_batch: 53
+last_completed_batch: 54
 last_cumulative_review: batches_49-51
+current_batch: 55