feat: phase 3+4 timeline animation + education entities

- Add education entities (A-Levels, MPharm) to constellation data
- Add 'education' node type with dashed border styling
- Create useTimelineAnimation hook with rAF scheduler + state machine
  (IDLE → PLAYING → PAUSED → HOLDING → RESETTING → loop)
- Chronological reveal: entities oldest-first with skill stagger,
  link draw-on, reinforcement pulse for already-visible skills
- Year indicator overlay (monospace, top-left)
- Multiplicative opacity: animation visibility × highlight emphasis
- Highlight system respects visibleNodeIdsRef (unrevealed stay hidden)
- Interaction pause/resume wired to animation hook
- Play/pause button (bottom-right, larger touch target on mobile)
- prefers-reduced-motion: shows final state immediately, no animation
- Remove Phase 2 entry animation (replaced by timeline animation)

src/components/constellation/constants.ts

@@ -39,6 +39,20 @@ export const ENTRY_ROLE_DURATION_MS = 300
 export const ENTRY_SKILL_STAGGER_MS = 30
 export const ENTRY_SKILL_DURATION_MS = 250
 
+// Timeline animation
+export const ANIM_ENTITY_REVEAL_MS = 600
+export const ANIM_SKILL_REVEAL_MS = 350
+export const ANIM_SKILL_STAGGER_MS = 60
+export const ANIM_LINK_DRAW_MS = 300
+export const ANIM_LINK_STAGGER_MS = 40
+export const ANIM_REINFORCEMENT_MS = 350
+export const ANIM_STEP_GAP_MS = 400
+export const ANIM_HOLD_MS = 3000
+export const ANIM_RESET_MS = 400
+export const ANIM_RESTART_DELAY_MS = 200
+export const ANIM_INTERACTION_RESUME_MS = 800
+export const ANIM_SETTLE_ALPHA = 0.05
+
 // Domain color map
 export const DOMAIN_COLOR_MAP: Record<string, string> = {
   clinical: '#059669',