chore: complete Phase 5 — update version, progress, and plan

- BootScene version bumped to v0.5.0
- PROGRESS.md updated with Phase 5 completion details
- IMPLEMENTATION-PLAN.md Phase 5 marked ✅
- Ready for Phase 6: Run Cycle

Co-authored-by: Cursor <cursoragent@cursor.com>

src/scenes/BootScene.ts

@@ -30,7 +30,7 @@ export class BootScene extends Phaser.Scene {
 
     // Version
     this.add
-      .text(cx, cy + 80, 'v0.4.0 — Phase 4: Player Systems', {
+      .text(cx, cy + 80, 'v0.5.0 — Phase 5: Creatures & Ecology', {
         fontSize: '12px',
         color: '#333333',
         fontFamily: 'monospace',