fix: remove discipline pool-drain model, add conversion stats UI per mana-conversion-spec

DISC-2: Removed old pool-drain model from discipline-slice.ts processTick()
- Disciplines no longer drain rawMana or element pools
- canProceedDiscipline() no longer checks mana sufficiency
- Removed auto-pause on insufficient mana from processTick()
- Removed drain display and auto-paused message from DisciplineCard.tsx
- Removed auto-paused log from gameStore.ts tick()

DISC-4: Audited crafting pipeline — no composite crafting logic remains
- craftComposite already removed from manaStore.ts (comment only)
- No other composite crafting references found

DISC-5: Added collapsible formula reference to Conversion Stats section
- Shows unified formula, multipliers, cost formulas, and constraints

DISC-6: Added per-element net regen summary line
- Shows 'Net Fire Regen: +0.50/hr − 0.15/hr = +0.35/hr' per element

DISC-7: Created dedicated 'Conversion Stats' section in Stats tab
- Renamed from 'Conversion Breakdown' to dedicated section header

DISC-8: Added detailed per-element regen breakdown to ManaDisplay
- Each element card now expandable to show produced rate and downstream drains
- New ElementRegenBreakdown type and elementRegenBreakdown prop

Tests: Updated 4 test files to reflect new no-drain behavior
- All 1090 tests pass

docs/circular-deps.txt

@@ -1,5 +1,5 @@
 # Circular Dependencies
-Generated: 2026-06-09T08:00:04.568Z
+Generated: 2026-06-09T08:14:36.361Z
 Found: 2 circular chain(s) — these MUST be fixed before modifying involved files.
 
 1. 1) stores/golem-combat-actions.ts > stores/golem-combat-helpers.ts