feat(01-02): add Phase-3/4 stub Protocols (anchor_verifier, safety_state, flight_recorder)

- anchor_verifier.protocol: AnchorVerifier + VerifierDecision dataclass
  (Phase 3 VERIFY-01..05 fills semantics)
- safety_state.protocol: SafetyAnchorStateMachine + SourceLabel enum
  (Phase 3 SAFE-01..06 fills implementation)
- flight_recorder.protocol: FlightRecorder + RecorderHealth enum +
  FdrExportResult (Phase 4 FDR-01..06 fills)
- Enum string values match REQUIREMENTS.md SAFE-01 / FDR-04
- Not registered in build_pipeline yet — Phase 1 only requires existence

src/gps_denied/components/anchor_verifier/protocol.py

@@ -0,0 +1,37 @@
+"""Protocol surface for the anchor_verifier component (Phase 3, VERIFY-01..05).
+
+Phase 1: stub only — semantics filled in Phase 3. The Protocol must
+exist now so the ARCH-01 directory inventory is complete at end of
+Phase 1.
+"""
+from __future__ import annotations
+
+from dataclasses import dataclass
+from typing import Protocol, runtime_checkable
+
+from gps_denied.hot_types.alignment_result import AlignmentResult
+from gps_denied.hot_types.satellite_anchor import SatelliteAnchor
+
+
+@dataclass(slots=True, frozen=True)
+class VerifierDecision:
+    """Result of an :meth:`AnchorVerifier.verify` call.
+
+    Phase 3 will refine the rejection-reason taxonomy (currently free-text:
+    ``too_few_inliers`` / ``mre_above_threshold`` / ``degenerate_homography``
+    / ``freshness_expired``).
+    """
+
+    accepted: bool
+    anchor: SatelliteAnchor | None = None
+    rejection_reason: str | None = None
+    inlier_count: int = 0
+    mean_reprojection_error_px: float = 0.0
+    homography_condition_number: float = 0.0
+
+
+@runtime_checkable
+class AnchorVerifier(Protocol):
+    """Geometry-gated anchor verifier. Filled in Phase 3."""
+
+    def verify(self, candidate: AlignmentResult) -> VerifierDecision: ...

src/gps_denied/components/flight_recorder/protocol.py

@@ -0,0 +1,40 @@
+"""Protocol surface for the flight_recorder component (Phase 4, FDR-01..06).
+
+Phase 1: stub only — Phase 4 lands the in-memory + disk implementations
+behind this Protocol.
+"""
+from __future__ import annotations
+
+from dataclasses import dataclass
+from enum import Enum
+from typing import Any, Protocol, runtime_checkable
+
+
+class RecorderHealth(str, Enum):
+    """Health tier of the flight-data recorder (FDR-04)."""
+
+    OK = "ok"
+    DEGRADED = "degraded"  # >= 90% storage
+    CRITICAL = "critical"  # storage limit reached
+
+
+@dataclass(slots=True, frozen=True)
+class FdrExportResult:
+    """Outcome of :meth:`FlightRecorder.export`."""
+
+    flight_id: str
+    segment_count: int
+    total_bytes: int
+    path: str | None = None  # set for DiskFlightRecorder, None for in-memory
+
+
+@runtime_checkable
+class FlightRecorder(Protocol):
+    """Append-only flight-data recorder per FDR-01. Filled in Phase 4."""
+
+    def append_event(self, event: dict[str, Any]) -> None: ...
+
+    def export(self) -> FdrExportResult: ...
+
+    @property
+    def health(self) -> RecorderHealth: ...

src/gps_denied/components/safety_state/protocol.py

@@ -0,0 +1,44 @@
+"""Protocol surface for the safety_state component (Phase 3, SAFE-01..06).
+
+Phase 1: stub only — the SafetyAnchorStateMachine becomes the
+authoritative source_label owner per SAFE-01 in Phase 3.
+"""
+from __future__ import annotations
+
+from enum import Enum
+from typing import Protocol, runtime_checkable
+
+from gps_denied.hot_types.position_estimate import PositionEstimate
+from gps_denied.hot_types.satellite_anchor import SatelliteAnchor
+
+
+class SourceLabel(str, Enum):
+    """Authoritative label for the provenance of a PositionEstimate (SAFE-01)."""
+
+    SATELLITE_ANCHORED = "satellite_anchored"
+    VO_EXTRAPOLATED = "vo_extrapolated"
+    DEAD_RECKONED = "dead_reckoned"
+
+
+@runtime_checkable
+class SafetyAnchorStateMachine(Protocol):
+    """Authoritative source_label owner per SAFE-01. Filled in Phase 3."""
+
+    @property
+    def source_label(self) -> SourceLabel: ...
+
+    @property
+    def anchor_age_ms(self) -> float: ...
+
+    @property
+    def can_persist_tile(self) -> bool: ...
+
+    def on_anchor_accepted(self, anchor: SatelliteAnchor) -> None: ...
+
+    def on_anchor_rejected(self, reason: str) -> None: ...
+
+    def on_vo_update(self, timestamp: float) -> None: ...
+
+    def on_visual_blackout(self) -> None: ...
+
+    def annotate(self, estimate: PositionEstimate) -> PositionEstimate: ...