[ASSET] Animation pass (critical animations only)

## Goal
Wichtigste Animationen erhöhen Lesbarkeit, ohne Bugs.

## Non-Goals
- Volle Animation-Suite (MVP ok)

## Tasks
- [ ] player idle/walk topdown
- [ ] 1–2 enemy anims
- [ ] hit/collect FX

## Acceptance Criteria
- [ ] Animationen laufen nur im passenden Mode
- [ ] keine handler duplication

## Test Evidence
- [ ] 20s clip: walk + hit FX

**Dependencies:** #17, #18, #19, #20, #21, #32