feat: remove Spells tab UI

- Remove Spells tab trigger from TabTriggers in page.tsx
- Remove TabsContent value='spells' block in page.tsx
- Remove lazy import of SpellsTab in page.tsx
- Change default activeTab from 'spells' to 'disciplines'
- Remove SpellsTab re-export from tabs/index.ts
- Remove SpellsTab re-export from game/index.ts
- Delete src/components/game/tabs/SpellsTab.tsx

Spell data (SPELLS_DEF, spells store state) preserved - spells still exist as enchantments.

docs/circular-deps.txt

@@ -1,5 +1,5 @@
 # Circular Dependencies
-Generated: 2026-06-08T13:03:26.382Z
+Generated: 2026-06-08T13:51:45.536Z
 Found: 1 circular chain(s) — these MUST be fixed before modifying involved files.
 
 1. 1) stores/golem-combat-actions.ts > stores/golem-combat-helpers.ts

docs/dependency-graph.json

@@ -1,6 +1,6 @@
 {
   "_meta": {
-    "generated": "2026-06-08T13:03:24.191Z",
+    "generated": "2026-06-08T13:51:43.381Z",
     "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."
   },

docs/project-structure.txt

@@ -145,7 +145,6 @@ Mana-Loop/
 │   │   │   │   ├── GuardianPactsTab.tsx
 │   │   │   │   ├── PrestigeTab.test.ts
 │   │   │   │   ├── PrestigeTab.tsx
-│   │   │   │   ├── SpellsTab.tsx
 │   │   │   │   ├── SpireSummaryTab.helpers.tsx
 │   │   │   │   ├── SpireSummaryTab.test.ts
 │   │   │   │   ├── SpireSummaryTab.tsx