feat: add equipment set bonuses and boss bounty runestones

- Define EquipmentSet type + computeSetBonuses utility in packages/types
- Add setId field to Equipment type and assign sets to 27 equipment items
- Create 9 named equipment sets (Iron Vanguard → Eternal Throne) with 2pc/3pc bonuses
- Apply set combat multiplier in boss route
- Apply set gold/click multipliers in tick engine and click handler
- Include set bonuses in anti-cheat delta validation
- Show active set bonus strip + set badge per card in EquipmentPanel
- Add boss first-kill bounty runestones (scaling 1–10 per boss tier)
- Update AboutPanel and IDEAS.md

IDEAS.md

@@ -20,7 +20,7 @@ A running list of planned features and content additions. Strike through items a
 
 ## 📦 Content Additions
 
-- [ ] **Equipment set bonuses** — Group existing equipment into named sets (e.g. "Shadow Infiltrator"). Wearing 2/3/4 pieces of a set grants escalating bonuses. Adds strategic depth without requiring lots of new items.
+- [x] **Equipment set bonuses** — Group existing equipment into named sets (e.g. "Shadow Infiltrator"). Wearing 2/3/4 pieces of a set grants escalating bonuses. Adds strategic depth without requiring lots of new items.
 
 - [ ] **The Codex / Lore Book** — Defeating bosses and completing quests unlocks lore entries about the world. Pure flavour, but gives the world depth and a collection mechanic. Show a ✨ notification when new lore unlocks.
 
@@ -43,7 +43,7 @@ A running list of planned features and content additions. Strike through items a
 3. ~~Daily challenges~~ ✅
 4. ~~Boss first-kill bounties~~ ✅
 5. ~~Milestone prestige bonuses~~ ✅
-6. Equipment set bonuses (medium effort)
+6. ~~Equipment set bonuses~~ ✅
 7. Auto-prestige toggle (prestige shop upgrade)
 8. The Codex / Lore Book (flavour, lower priority)
 9. Second prestige layer / Transcendence (big feature, save for later)