fix: remove dead GameContext system and orphaned MemorySlotPicker

GameContext (Provider, hooks, context-create, types) was never wired into
the app — no layout or page wrapped children with GameProvider. The only
consumer, MemorySlotPicker, was itself orphaned (never imported/rendered).
The app uses direct Zustand hooks throughout. Removes 6 dead files.

Fixes #65

docs/circular-deps.txt

@@ -1,5 +1,5 @@
 # Circular Dependencies
-Generated: 2026-05-18T13:14:04.833Z
+Generated: 2026-05-18T15:51:10.807Z
 Found: 1 circular chain(s) — these MUST be fixed before modifying involved files.
 
 1. Processed 123 files (1.2s) (29 warnings)

docs/dependency-graph.json

@@ -1,6 +1,6 @@
 {
   "_meta": {
-    "generated": "2026-05-18T13:14:03.496Z",
+    "generated": "2026-05-18T15:51:09.351Z",
     "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

@@ -63,11 +63,6 @@ Mana-Loop/
 │   │   └── page.tsx
 │   ├── components/
 │   │   ├── game/
-│   │   │   ├── GameContext/
-│   │   │   │   ├── Provider.tsx
-│   │   │   │   ├── context-create.ts
-│   │   │   │   ├── hooks.ts
-│   │   │   │   └── types.ts
 │   │   │   ├── LootInventory/
 │   │   │   │   ├── BlueprintsSection.tsx
 │   │   │   │   ├── EquipmentItem.tsx
@@ -106,7 +101,6 @@ Mana-Loop/
 │   │   │   │   ├── debug-context.tsx
 │   │   │   │   └── index.tsx
 │   │   │   ├── shared/
-│   │   │   │   └── MemorySlotPicker.tsx
 │   │   │   ├── tabs/
 │   │   │   │   ├── ActivityLog.tsx
 │   │   │   │   ├── DisciplinesTab.tsx
@@ -118,7 +112,6 @@ Mana-Loop/
 │   │   │   ├── CalendarDisplay.tsx
 │   │   │   ├── ConfirmDialog.tsx
 │   │   │   ├── CraftingProgress.tsx
-│   │   │   ├── GameContext.tsx
 │   │   │   ├── GameToast.tsx
 │   │   │   ├── ManaDisplay.tsx
 │   │   │   ├── SpellsTab.tsx