feat(cardshed): bootstrap deterministic core rules engine (#139)

.claude/rules/commit-format.md

@@ -23,6 +23,7 @@ type(scope): description (#issue)
 | `mcp` | KNOWRAG `apps/mcp/` |
 | `ingest` | KNOWRAG ingestion pipeline (crawling/embedding/chunking) |
 | `reliquary` | Anything under `@lab/ll-RELIQUARY/` (browser-based collectable artifact game) |
+| `cardshed` | Anything under `@lab/ll-CARDSHED/` (CARD SHED card game — pure-logic core + UI + bots) |
 | `repo` | Repo-wide hygiene (gitignore, scaffolding, untracked-path triage) |
 | `platform` | `.bin/`, `.shared/`, top-level CLI |
 | `stacks` | Anything under `@ops/`, `@dev/`, `@prod/` (any single zone-stack) |

@lab/ll-CARDSHED/apps/core/.gitignore

@@ -0,0 +1,5 @@
+node_modules/
+dist/
+*.log
+.DS_Store
+coverage/

@lab/ll-CARDSHED/apps/core/eslint.config.js

@@ -0,0 +1,50 @@
+import tseslint from "typescript-eslint";
+
+const determinismBans = [
+  {
+    selector: "MemberExpression[object.name='Math'][property.name='random']",
+    message: "Math.random is forbidden in core/**. Use mulberry32(seed) via prng.ts.",
+  },
+  {
+    selector: "MemberExpression[object.name='Date'][property.name='now']",
+    message: "Date.now is forbidden in core/**. The engine has no concept of time.",
+  },
+  {
+    selector: "NewExpression[callee.name='Date']",
+    message: "new Date() is forbidden in core/**. The engine has no concept of time.",
+  },
+  {
+    selector: "MemberExpression[object.name='performance'][property.name='now']",
+    message: "performance.now is forbidden in core/**.",
+  },
+  {
+    selector:
+      "MemberExpression[object.name='crypto'][property.name='getRandomValues']",
+    message: "crypto.getRandomValues is forbidden in core/**.",
+  },
+];
+
+export default tseslint.config(
+  {
+    ignores: ["node_modules", "dist", "scripts/**", "**/__tests__/**"],
+  },
+  ...tseslint.configs.recommended,
+  {
+    files: ["src/core/**/*.ts"],
+    languageOptions: {
+      parserOptions: {
+        project: false,
+        ecmaVersion: 2022,
+        sourceType: "module",
+      },
+    },
+    rules: {
+      "no-restricted-syntax": ["error", ...determinismBans],
+      "@typescript-eslint/no-unused-vars": [
+        "error",
+        { argsIgnorePattern: "^_", varsIgnorePattern: "^_" },
+      ],
+      "@typescript-eslint/no-explicit-any": "warn",
+    },
+  },
+);