improvement(lint): enforce noUnusedVariables and noUnusedFunctionParameters repo-wide

Enable both rules as errors at the root with no autofix, so bun run lint
never mass-renames bindings to _x, and ignoreRestSiblings so the
{ a, ...rest } omit idiom stays legal. The packages/** override is now
redundant and removed. Document the rule in CLAUDE.md.

Author: waleedlatif1

CLAUDE.md

@@ -88,6 +88,7 @@ The `'use client'` server boundary, the app/worker runtime env split, and featur
 - **Naming**: components PascalCase (`WorkflowList`); hooks `use*`; files kebab-case (`workflow-list.tsx`); constants SCREAMING_SNAKE_CASE; interfaces PascalCase with a suffix (`WorkflowListProps`); stores `stores/<feature>/store.ts`.
 - **Imports**: absolute (`@/...`) only, never relative. A folder with 3+ exports gets an `index.ts` barrel; never re-export from a non-barrel file. `import type` for type-only imports. Order and lazy-loading through barrels: `.claude/rules/sim-imports.md`.
 - **TypeScript**: no `any` (use precise types or `unknown` with guards); a props interface for every component; `as const` for constant objects/arrays; explicit ref types (`useRef<HTMLDivElement>(null)`).
+- **Unused bindings** fail lint (biome `noUnusedVariables`, `noUnusedFunctionParameters`): delete the dead variable, import, or parameter and update callers; write `catch {}` when the error is unused. Prefix `_` only for a parameter that must hold its position because a later one is used. `const { a, ...rest } = obj` to omit keys is allowed. The rules carry no autofix, so `bun run lint` will not rename anything for you.
 - **Components**: `'use client'` only for hooks or browser APIs. Structure order, extraction thresholds, and list-render rules: `.claude/rules/sim-components.md`. Render-performance idioms (lazy-init refs, hoisting, `Map` pre-indexing, `[...arr].sort()` never `toSorted()` on client paths): `.claude/rules/sim-react-performance.md`. For effect/state/memo/callback anti-patterns use the `/you-might-not-need-*` skills and verify against the running UI.
 - **State ownership**: React Query owns server data — never `useState` + `fetch`; shareable client view-state (tabs, filters, search, pagination, selected id) lives in the URL via `nuqs`; Zustand owns global client state; `useState` owns UI-only state. Hooks: `.claude/rules/sim-hooks.md`. Stores (`devtools`, `persist` only with an explicit `partialize` whitelist, workflow value invariants): `.claude/rules/sim-stores.md`. URL state: `.claude/rules/sim-url-state.md`.
 - **Utils**: inline a helper with one consumer; create `utils.ts` when 2+ files share it — in `lib/` (app-wide) or `feature/utils/` (feature-scoped). Check `lib/` before writing a new one.

biome.json

@@ -99,8 +99,12 @@
       },
       "correctness": {
         "useExhaustiveDependencies": "off",
-        "noUnusedFunctionParameters": "off",
-        "noUnusedVariables": "off"
+        "noUnusedFunctionParameters": { "level": "error", "fix": "none" },
+        "noUnusedVariables": {
+          "level": "error",
+          "fix": "none",
+          "options": { "ignoreRestSiblings": true }
+        }
       },
       "security": {
         "noDangerouslySetInnerHtml": "off"
@@ -146,17 +150,6 @@
       "includes": ["apps/sim/app/_styles/tailwind.css"],
       "linter": { "enabled": false },
       "formatter": { "enabled": false }
-    },
-    {
-      "includes": ["packages/**"],
-      "linter": {
-        "rules": {
-          "correctness": {
-            "noUnusedFunctionParameters": "error",
-            "noUnusedVariables": "error"
-          }
-        }
-      }
     }
   ],
   "javascript": {