refactor: remove skill system leftovers, migrate click mana to discipline perk

- Simplified getMeditationBonus() to continuous ramp formula
- Added click-mana capped perk to Mana Circulation discipline
- Removed manaWell/manaFlow/manaSpring skill reads and prestige upgrades
- Removed all skill fields from GameState and GameActionType
- Updated all call sites and tests (916 tests passing)

Closes #174

docs/circular-deps.txt

@@ -1,11 +1,4 @@
 # Circular Dependencies
-Generated: 2026-05-28T07:32:48.513Z
-Found: 1 circular chain(s) — these MUST be fixed before modifying involved files.
+Generated: 2026-05-28T07:47:51.159Z
 
-1. 1) effects/discipline-effects.ts > stores/discipline-slice.ts
-
-## How to fix
-1. Identify which import in the chain can be extracted to a shared types/utils file.
-2. Move the shared type or function there.
-3. Both files import from the new shared module instead of each other.
-4. Run: bunx madge --circular src/lib/game  (should return clean)
+No circular dependencies found. ✅

docs/dependency-graph.json

@@ -1,6 +1,6 @@
 {
   "_meta": {
-    "generated": "2026-05-28T07:32:46.775Z",
+    "generated": "2026-05-28T07:47:49.204Z",
     "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."
   },
@@ -528,7 +528,6 @@
       "data/disciplines/enchanter.ts",
       "data/disciplines/fabricator.ts",
       "data/disciplines/invoker.ts",
-      "effects/discipline-effects.ts",
       "types.ts",
       "types/disciplines.ts",
       "utils/discipline-math.ts",