implicit: implement Implicit 9.2, 10.1, 10.2 - env validation and pre-commit hooks

- Implicit 9.2: Verified env validation already implemented (Zod schema with clear errors)
- Implicit 10.1: Added type checking to pre-commit hook (blocks on errors, allows warnings)
- Implicit 10.2: Added linting to pre-commit hook (blocks on errors, allows warnings)
- Pre-commit hook now runs: type generation, type checking, linting
- Prevents commits with TypeScript or linting errors
- Provides helpful error messages and tips
- Note: Pre-existing TypeScript errors in codebase will block commits until fixed

.husky/pre-commit

@@ -3,3 +3,19 @@
 # Generate TypeScript types from OpenAPI spec before commit
 # This ensures types are always up-to-date with the backend API
 cd apps/web && bash scripts/generate-types.sh
+
+# Implicit 10.1: Type checking
+# Prevent commits with TypeScript errors (warnings are allowed)
+cd apps/web && npm run typecheck 2>&1 | grep -q "error TS" && {
+  echo "❌ Type checking failed. Please fix TypeScript errors before committing."
+  echo "💡 Run 'npm run typecheck' to see all errors."
+  exit 1
+} || true
+
+# Implicit 10.2: Linting
+# Prevent commits with linting errors (warnings are allowed)
+cd apps/web && npm run lint 2>&1 | grep -q "error" && {
+  echo "❌ Linting failed. Please fix linting errors before committing."
+  echo "💡 Tip: Run 'npm run lint:fix' to automatically fix some issues."
+  exit 1
+} || true

EXHAUSTIVE_TODO_LIST.md

@@ -4922,12 +4922,19 @@ If any task fails:
     - **Result**: Complete environment variable documentation for developers
   - **Rollback**: Delete .env.example
 
-- [ ] **Implicit 9.2**: Add validation for environment variables
+- [x] **Implicit 9.2**: Add validation for environment variables
   - **Scope**: `apps/web/src/config/env.ts` - Validate required variables on startup
-  - **Dependencies**: None
+  - **Dependencies**: None ✅
   - **Risk**: LOW 🔒
-  - **Validation**: Missing variables cause clear errors
-  - **Rollback**: Remove validation
+  - **Validation**: ✅ Environment variable validation already implemented:
+    - Uses Zod schema (`envSchema`) to validate all environment variables
+    - Validates URL format (absolute URLs or paths starting with /)
+    - Provides default values for all variables
+    - Throws clear error messages with detailed validation errors
+    - Logs validation errors using logger
+    - All variables are validated on module load (startup)
+    - **Result**: Complete environment variable validation with clear error messages
+  - **Rollback**: N/A (already implemented)
 
 ### Implicit Task 10: Update Git Hooks
 - [ ] **Implicit 10.1**: Add pre-commit hook for type checking