[AZ-342] C2.5 ReRankStrategy: Protocol + DTOs + factory + composition

Foundational scaffolding for the InlierCountReRanker (AZ-343) and
the future C3 CrossDomainMatcher consumer (AZ-344). No concrete
re-ranker is implemented here.

* ReRankStrategy Protocol (single rerank(frame, vpr_result, n,
  calibration) -> RerankResult method) with all 8 invariants in the
  docstring — notably INV-8 drop-and-continue (per-candidate failure
  NEVER propagates unless every candidate fails).
* DTOs moved to L1 _types/rerank.py — RerankCandidate, RerankResult;
  frozen+slots; tuple-not-list for RerankResult.candidates; tile_id
  encoded as (zoom_level, lat, lon) tuple to keep _types/ free of any
  c6_tile_cache (L3) import per module-layout.md.
* Error family: RerankError + RerankBackboneError +
  RerankAllCandidatesFailedError. Only RerankAllCandidatesFailedError
  escapes rerank(); RerankBackboneError is caught inside the per-
  candidate loop, logged ERROR, FDR-stamped, candidate dropped.
* C2_5RerankConfig (strategy enum default "inlier_count", top_n int
  default 3) with strict validation at load; registered into
  Config.components on c2_5_rerank import.
* build_rerank_strategy(config, *, tile_store, lightglue_runtime)
  factory: 1-strategy resolution table, lazy import,
  BUILD_RERANK_<variant> gate, ImportError → StrategyNotAvailableError
  mapping. The shared LightGlueRuntime is constructor-injected
  (R14 fix: neither C2.5 nor C3 owns its lifecycle).

Renamed the Protocol from the existing stub "RerankStrategy" to
"ReRankStrategy" to match the contract; updated module-layout.md.
Removed the legacy RerankResult shape from _types/vpr.py — the
v1.0.0 shape lives in _types/rerank.py.

Excluded per task spec:
* Concrete InlierCountReRanker (AZ-343).
* C3 matcher protocol task (AZ-344, next in batch).
* AC-9 single-thread binding + AC-10 LightGlueRuntime identity-share
  between C2.5/C3 — deferred per task spec Risk 3 until the generic
  compose_root thread-binding registry and the C3 factory both land.

Tests: AC-1..AC-8 + AC-11 + NFR-perf-factory in
tests/unit/c2_5_rerank/test_protocol_conformance.py. The legacy
smoke test is removed. Full sweep: 997 passed (one pre-existing
flake in test_az296_takeoff_abort, subprocess timing, unrelated to
this commit; passes in isolation).

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

_docs/02_document/contracts/c2_5_rerank/rerank_strategy_protocol.md

@@ -4,7 +4,7 @@
 **Producer task**: AZ-342 (`ReRankStrategy` Protocol + factory + composition)
 **Consumer tasks**: AZ-343 (`InlierCountReRanker` impl); downstream c3_matcher (epic AZ-257 / E-C3 — TBD at AZ-257 decompose time) which consumes `RerankResult`
 **Version**: 1.0.0
-**Status**: draft, awaiting AZ-342 implementation
+**Status**: v1.0.0 (AZ-342 implemented 2026-05-12)
 **Last Updated**: 2026-05-10
 **Module-layout home**: `src/gps_denied_onboard/components/c2_5_rerank/interface.py` (Protocol), `src/gps_denied_onboard/components/c2_5_rerank/__init__.py` (re-exports), `src/gps_denied_onboard/runtime_root/rerank_factory.py` (factory)
 
@@ -75,31 +75,29 @@ class ReRankStrategy(Protocol):
 
 ```python
 from dataclasses import dataclass
-from uuid import UUID
-import numpy as np
 
 
 @dataclass(frozen=True, slots=True)
 class RerankCandidate:
     """One re-rank survivor. Carries the C2-stage descriptor_distance forward for FDR provenance plus the new inlier_count from single-pair LightGlue."""
 
-    tile_id: tuple  # composite (zoomLevel, lat, lon); see C6 TileRecord
-    inlier_count: int  # single-pair LightGlue inliers; > 0 for any survivor
-    descriptor_distance: float  # carried forward from C2's VprCandidate
-    descriptor_dim: int  # carried forward from C2 for sanity assertions
-    tile_pixels_handle: object  # opaque page-cache-backed pixel reference; see C6 TileStore contract
+    tile_id: tuple[int, float, float]  # composite (zoom_level, lat, lon); matches c6_tile_cache.TileId. tuple form keeps _types/ free of an L1→L3 import per module-layout.md.
+    inlier_count: int                  # single-pair LightGlue inliers; > 0 for any survivor
+    descriptor_distance: float         # carried forward from C2's VprCandidate
+    descriptor_dim: int                # carried forward from C2 for sanity assertions
+    tile_pixels_handle: object         # opaque page-cache-backed pixel reference; see C6 TileStore contract
 
 
 @dataclass(frozen=True, slots=True)
 class RerankResult:
     """Top-N survivors from `ReRankStrategy.rerank`. Consumed by C3 CrossDomainMatcher."""
 
-    frame_id: UUID
-    candidates: list[RerankCandidate]  # 0 < len <= n; sorted descending by inlier_count, ties broken by descriptor_distance ascending
-    reranked_at: int  # monotonic_ns
-    rerank_label: str  # non-empty; matches BUILD_RERANK_<variant> lowercase (e.g., "inlier_count")
-    candidates_input: int  # len(vpr_result.candidates) at entry — for FDR observability
-    candidates_dropped: int  # candidates_input - len(candidates)
+    frame_id: int                          # echoes NavCameraFrame.frame_id (int across the pipeline)
+    candidates: tuple[RerankCandidate, ...]  # 0 < len <= n; descending by inlier_count, ties broken by descriptor_distance ascending. tuple (not list) so the frozen+slots invariant holds.
+    reranked_at: int                       # monotonic_ns from injected Clock
+    rerank_label: str                      # non-empty; matches BUILD_RERANK_<variant> lowercase
+    candidates_input: int                  # len(vpr_result.candidates) at entry — for FDR observability
+    candidates_dropped: int                # candidates_input - len(candidates)
 ```
 
 ### Error Hierarchy (in `c2_5_rerank/errors.py`)

_docs/02_document/module-layout.md

@@ -57,8 +57,8 @@ Bootstrap reference: `_docs/02_tasks/todo/AZ-263_initial_structure.md`. Architec
 - **Epic**: AZ-256 (E-C2.5 Rerank)
 - **Directory**: `src/gps_denied_onboard/components/c2_5_rerank/`
 - **Public API**:
-  - `__init__.py` (re-exports `RerankStrategy`, `RerankResult`)
-  - `interface.py` (`RerankStrategy` Protocol)
+  - `__init__.py` (re-exports `ReRankStrategy`, `RerankResult`, `RerankCandidate`)
+  - `interface.py` (`ReRankStrategy` Protocol)
 - **Internal**:
   - `inlier_based_reranker.py` (single-pair LightGlue inlier count K=10→N=3)
 - **Owns**: `src/gps_denied_onboard/components/c2_5_rerank/**`, `tests/unit/c2_5_rerank/**`