fix: resolve elemental mana conversion pause bug (#348)

Two root causes fixed:
1. gameStore.ts: computeRegen now receives actual attunements instead of empty {}, so rawGrossRegen includes attunement contributions (was ~2/hr, now correct 3000+/hr)
2. gameStore.ts buildConversionParams: use rawManaRegen with level scaling (1.5^(level-1)) instead of conversionRate for per-element grossRegen
3. LeftPanel.tsx: same grossRegen fix + include attunement regen in rawGrossRegen display
4. ElementStatsSection.tsx: same grossRegen fix
5. useGameDerived.ts: pass actual attunements to computeRegen for baseRegen calculation

Added regression test: conversion-pause-bug-regression.test.ts (7 tests)

docs/dependency-graph.json

@@ -1,6 +1,6 @@
 {
   "_meta": {
-    "generated": "2026-06-10T08:14:31.514Z",
+    "generated": "2026-06-10T08:50:54.740Z",
     "description": "Import dependency graph for src/lib/game. Keys are files, values are arrays of files they import.",
     "usage": "To find what a file affects, search for its path in the VALUES. To find what a file depends on, look at its KEY entry."
   },