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/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",