v4.3.0 release prep: version bumps + all 8 pre-release code-review fixes

[TheAngryRaven]

Summary

Release housekeeping plus all 8 findings from the pre-release code review of BETA vs master, so v4.3.0 ships clean.

Release prep

• library.properties: version=4.2.0 → 4.3.0
• Doxyfile: PROJECT_NUMBER was stale at 4.0.0 → 4.3.0
• CHANGELOG.md: [Unreleased] entries moved under ## [4.3.0] – 2026-08-10 (now including the fixes below), tag link added
• CLAUDE.md: version line → 4.3.0

Correctness fixes

• SprintTimer same-fix crossing order: completed crossings now dispatch ordered by their interpolated crossing timestamps (wrap-aware; ties: splits → finish → start) instead of a fixed finish-first order. Pre-fix, a split zone and the finish zone exited on the same GPS fix (overlapping zones at low fix rate — a configuration SprintTimer explicitly supports) closed the run before its final split was booked, wrongly invalidating the run's segment data; a split coinciding with a cancel-restart could book a wrapped near-day-length segment time.
• CourseManager::selectCourse() stale-timer reactivation: a timer frozen by the Lap Anything fallback (or pruning) is now reset before re-activation. Pre-fix its frozen raceStarted/lap-start/position snapshot closed a bogus multi-minute "lap", permanently poisoned bestLapTime, and credited never-driven odometer distance.

Contract fixes

• SprintTimer::loop() return now matches DovesLapTimer::loop(): 0 only while inside a crossing zone; the zone-exit fix returns -1.
• Duck-typed getter surface completed: added getCurrentLapStartTime(), getCurrentLapOdometerStart(), isStartFinishLineConfigured() to SprintTimer — the "full DovesLapTimer getter surface" claim is now true.
• CI CXXFLAGS drift: test/Makefile gained EXTRA_CXXFLAGS (appended); unit-tests.yml's kill-switch pass uses make run EXTRA_CXXFLAGS=-DDOVES_DISABLE_DEBUG instead of a hardcoded copy of the Makefile's flags.

Hygiene

• Five copy-pasted DOVES_DISABLE_DEBUG template blocks deduplicated into shared src/DovesDebug.h (DOVES_DEBUG_TEMPLATES() macro).
• Dead SprintTimer::_crossingThresholdMeters member removed.
• CLAUDE.md staleness: CI matrix compiles 4 examples (not 3); five debug-printing classes (not six, CourseDetector has none); DovesDebug.h documented.

Type of change

• Bug fix
• New feature
• Refactor (no behavior change)
• Docs / examples
• CI / tooling

Testing

• cd test && make run passes locally — and passes with EXTRA_CXXFLAGS=-DDOVES_DISABLE_DEBUG
• Added regression tests, each verified to fail against the pre-fix code:
  • test_sprint_timer.cpp::same_fix_split_and_finish_dispatch_in_crossing_order
  • test_sprint_timer.cpp::loop_return_matches_circuit_contract
  • test_course_manager.cpp::select_course_after_fallback_resets_stale_timer
  • plus duck-typed getter assertions in duck_typed_surface_matches_run_surface
• Timing output unchanged — Layer-3 NMEA replay goldens (and the sprint differential replay) all green

Checklist

• Doc comments updated for any public API changes (new getters, loop() return doc)
• README.md — N/A (its getter-surface claim becomes true; no text change needed)
• CHANGELOG.md updated (Fixed/Changed entries under [4.3.0])
• No new heap allocation in the GPS hot path (the dispatch sort is a 4-element stack array + insertion sort)

Notes for reviewers

Merge into BETA before PR #49 (BETA → master), then tag v4.3.0 after #49 lands. The dispatch-order fix intentionally changes behavior only when two lines complete on the same fix — the NMEA replay goldens pin that normal single-completion behavior is untouched.

🤖 Generated with Claude Code

https://claude.ai/code/session_01TQK29n1LCebSUxf1nD12FW

[github-actions]

GCC Code Coverage Report

📂 Overall coverage

Metric	Coverage
Lines	🟡 1465/1712 (85.6%)
Functions	🟡 242/296 (81.8%)
Branches	🔴 659/1050 (62.8%)

📄 File coverage

File	Lines	Functions	Branches
src/CourseDetector.cpp	🟢 98/104 (94.2%)	🟢 18/20 (90.0%)	🟡 39/46 (84.8%)
src/CourseManager.cpp	🟡 154/173 (89.0%)	🟡 18/24 (75.0%)	🟡 79/102 (77.5%)
src/CourseManager.h	🟢 33/33 (100.0%)	🟢 11/11 (100.0%)	🔴 11/22 (50.0%)
src/CrossingEngine.cpp	🟢 185/198 (93.4%)	🟢 11/12 (91.7%)	🔴 103/172 (59.9%)
src/CrossingEngine.h	🟡 91/103 (88.3%)	🟡 30/34 (88.2%)	🔴 31/68 (45.6%)
src/DovesLapTimer.cpp	🟡 294/362 (81.2%)	🔴 38/54 (70.4%)	🔴 161/254 (63.4%)
src/DovesLapTimer.h	🔴 53/91 (58.2%)	🟡 18/24 (75.0%)	🔴 14/40 (35.0%)
src/GeoMath.h	🟢 49/52 (94.2%)	🟢 7/7 (100.0%)	🟡 32/38 (84.2%)
src/SprintTimer.cpp	🟡 271/321 (84.4%)	🟡 37/48 (77.1%)	🔴 125/188 (66.5%)
src/SprintTimer.h	🟢 57/63 (90.5%)	🟢 23/25 (92.0%)	🔴 17/38 (44.7%)
src/WaypointLapTimer.cpp	🟡 159/188 (84.6%)	🟡 24/29 (82.8%)	🔴 40/66 (60.6%)
src/WaypointLapTimer.h	🟡 21/24 (87.5%)	🟡 7/8 (87.5%)	🔴 7/16 (43.8%)