Power-up drops: Magnet, Double Jump, Bubble Shield

[cmalpass]

What

Stomped enemies now drop a glowing capsule on a 25% roll, introducing three timed power-ups:

• Magnet (8 s) — crystals within 150 px home in at 520 px/s
• Double Jump (15 s) — one extra air jump (600 px/s), resets on landing
• Bubble Shield — absorbs the next hit with a pop, grants half-invulnerability, no heart lost

Capsules bob and glow in the world, blink during their final 2 seconds, and evaporate with a particle poof after 10 s. Active effects render as HUD chips under the heart panel (icon + draining timer bar). New SFX: rising power-up chime and bubble pop. Effects clear on respawn; capsules left in the field persist until expiry.

Implementation

• src/powerup.ts (new) — drop table (rollDrop, single injectable rng draw decides drop + type uniformly), capsule entity, shared icon renderer
• src/player.ts — magnet/double-jump/bubble state, air double-jump branch, magnet in the crystal loop, capsule pickup, bubble absorb in damage() (after god-mode check), stomp drop hook
• src/level.ts — capsule array, spawn, update (collect/expiry), reset
• src/config.ts — CFG.powerup tuning block
• src/audio.ts — powerup + bubblePop SFX
• src/game.ts — world render + HUD chips

Validation (local gate — CI is failing for pre-existing unrelated reasons)

• npm run typecheck ✓
• npm test — 193 passed (175 baseline + 18 new) ✓
• npm run build ✓ (128.96 kB / 39.66 kB gzip, single file)
• npm run lint ✓
• Headless Playwright E2E: HUD chips with all 3 active effects; magnet pulls and collects a real crystal; double jump sets airJumps with correct impulse; bubble absorbs a hit (hearts 3→3, invulnT set); forced stomp drop → capsule → same-frame pickup → fresh magnet timer (stomps: 1); field capsule screenshot. Zero page errors.

Screenshots: /tmp/tinyrex-e2e/01-hud-chips.png … 06-capsule-field.png