Exploids v0.12.0

• Fixed-timestep simulation: the game loop now advances in fixed steps (1/120 s) driven by a
  time accumulator, decoupled from the display refresh rate, instead of integrating one variable
  step per frame. On 120 Hz this is effectively one step per frame as before; on other refresh
  rates the simulation stays consistent.
• Because every step is the same length, a replay no longer needs the recorded per-frame dt
  sequence — it depends only on (seed + inputs). Replay format bumped to v3; older replays
  (v2, variable timestep) are rejected as incompatible.
• The headless GIF renderer drives the simulation one fixed step at a time and picks a capture
  stride automatically so the GIF plays in real time (--stride still overrides).
• Replays are now auto-saved to disk on every game over (not only high-score runs), under
  ~/Library/Application Support/Exploids/replays, so a good run can be turned into a GIF even if
  it didn't make the board. New CLI --render-last-replay --out <gif> renders the most recent one.
• New CLI --reset-highscores clears the saved high-score list (when the board fills with
  unbeatable scores).
• No gameplay-balance changes intended; this is an engine/feel change to be confirmed by playtest.

Exploids v0.11.1

• Replay fix: the auto-fire setting is now recorded in a replay and restored on playback. Before
  this, a run played with auto-fire on would not reproduce (the replayed ship barely fired and died
  early). Replay format bumped to v2; pre-fix replays are rejected as incompatible.
• Replay GIF renderer gained --from <frame>, --max-frames <n> and --auto-fire options, plus a
  --replay-verify diagnostic.
• Note: faithful replay requires the exact binary that recorded the run — a rebuilt binary can drift
  (floating-point reproducibility is binary-specific). In-app replays and GIFs from the same
  installed build are reliable.

Exploids v0.6.1

• Pixel font (Press Start 2P) for the EXPLOIDS / GAME OVER headings.
• High-score name entry fix (first responder).
• Reworked object glossary: every power-up listed individually, with a title strip.
• Fixes: extra life with gravity wells, entzerrtes start-screen layout, "#" extra-life cheat (for testing).