feat: Period labels, faceoff wins, and penalty queue

[JRemitz]

Summary

• Configurable period labels — sport-specific defaults (e.g. hockey: 1, 2, 3, OT, OT2, OT3, OT4) with external file override via period_labels.txt. "Edit..." button in Game Settings opens the file in the user's default text editor. File watcher applies changes live.
• Faceoff wins counter — home/away tracking for hockey and lacrosse, displayed below SOG in dock UI. Includes +/- buttons, 4 OBS hotkeys, home_faceoffs.txt/away_faceoffs.txt output files, JSON persistence, and tooltips on all stat rows.
• Penalty queue — only 2 penalties per team tick simultaneously (SCOREBOARD_MAX_RUNNING_PENALTIES), matching hockey rules. Additional penalties queue and auto-start when earlier ones expire. Dock UI shows queued penalties with "(queued)" suffix. Text file output shows only running penalties.
• Fix: Start/Stop button state — button now resets to green "Start" when clock auto-stops at 0:00 (previously stayed red "Stop").
• Fix: Penalty-clock coupling — penalty timers freeze when period clock reaches 0:00 (previously kept ticking after auto-stop).

Test plan

• make dev — all 7 test binaries pass
• make coverage — 100% line coverage on scoreboard-core.c
• make install && make run — verify in OBS:
  • Hockey: FO row visible below SOG, faceoff +/- works, hotkeys work
  • Basketball: FO row hidden
  • Add 3 penalties → only 2 tick, 3rd shows "(queued)" in dock
  • Let one expire → 3rd auto-starts
  • Clock reaches 0:00 → button resets to green, penalties freeze
  • Game Settings → "Edit..." opens period_labels.txt
  • Edit labels externally → dock updates live
• Reeln plugin tests: uv run pytest tests/ — 81 tests pass

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