Implement four feature phases:
Phase 1 - Pause menu: extract bitmap font into shared engine/font
module, add MODE_PAUSED with Resume/Restart/Quit overlay.
Phase 2 - Laser turret hazard: ENT_LASER_TURRET with charge/fire/
cooldown state machine, per-pixel beam raycast, two variants (fixed
and tracking). Registered in entity registry with editor icons.
Phase 3 - Charger and Spawner enemies: charger ground patrol with
detect/telegraph/charge/stun cycle (2s charge timeout), spawner that
periodically creates grunts up to a global cap of 3.
Phase 4 - Mars campaign: two handcrafted levels (mars01 surface,
mars02 base), mars_tileset.png, PARALLAX_STYLE_MARS with salmon sky
and red mesas, THEME_MARS_SURFACE/THEME_MARS_BASE for the procedural
generator with per-theme gravity/tileset/parallax. Moon campaign now
chains moon03 -> mars01 -> mars02 -> victory.
Also fix review findings: deterministic seed on generated level
restart, NULL checks on calloc in spawn functions, charge timeout
to prevent infinite charge on flat terrain, and stop suppressing
stderr in Makefile web-serve target so real errors are visible.
Introduce moon01.lvl as the starting level — a pure jump-and-run intro
with no gun and no enemies, just platforming over gaps and dodging falling
asteroids. The player picks up their gun upon transitioning to level01.
New features:
- Moon tileset and PARALLAX_STYLE_MOON with crater terrain backgrounds
- Asteroid entity (ENT_ASTEROID): falls from sky, damages on contact,
explodes on ground with particles, respawns after delay
- PLAYER_UNARMED directive disables gun for the level
- Pit rescue mechanic: falling costs 1 HP and auto-dashes upward
- Gun powerup entity type for future armed-pickup levels
- Segment-based procedural level generator with themed rooms
- Extended editor with entity palette and improved tile cycling
- Web shell improvements for Emscripten builds
