Align repo config with global development standards

- Add missing tsconfig strictness flags (noUncheckedIndexedAccess,
  exactOptionalPropertyTypes, noImplicitOverride,
  noPropertyAccessFromIndexSignature) and fix all resulting type errors
- Replace ESLint/Prettier with oxlint 1.48.0 and oxfmt 0.33.0
- Pin all frontend and backend dependencies to exact versions
- Pin GitHub Actions to SHA hashes with persist-credentials: false
- Fix CI Python version mismatch (3.12 -> 3.14) and ruff target-version
- Add vitest 4.0.18 with jsdom environment for frontend testing
- Add ty 0.0.17 for Python type checking (non-blocking in CI)
- Add actionlint and zizmor CI job for workflow linting and security audit
- Add Dependabot config for npm, pip, and github-actions
- Update CLAUDE.md and pre-commit hooks to reflect new tooling
- Ignore Claude Code sandbox artifacts in gitignore

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/components/StepIndicator.tsx

@@ -20,10 +20,7 @@ export function StepIndicator({
           const isCurrent = step === currentStep
 
           return (
-            <li
-              key={label}
-              className={`flex items-center ${i < steps.length - 1 ? 'flex-1' : ''}`}
-            >
+            <li key={label} className={`flex items-center ${i < steps.length - 1 ? 'flex-1' : ''}`}>
               <button
                 type="button"
                 onClick={() => isCompleted && onStepClick(step)}
@@ -53,11 +50,7 @@ export function StepIndicator({
                       stroke="currentColor"
                       strokeWidth={3}
                     >
-                      <path
-                        strokeLinecap="round"
-                        strokeLinejoin="round"
-                        d="M5 13l4 4L19 7"
-                      />
+                      <path strokeLinecap="round" strokeLinejoin="round" d="M5 13l4 4L19 7" />
                     </svg>
                   ) : (
                     step
@@ -68,9 +61,7 @@ export function StepIndicator({
               {i < steps.length - 1 && (
                 <div
                   className={`flex-1 h-0.5 mx-3 ${
-                    step < currentStep
-                      ? 'bg-blue-600'
-                      : 'bg-gray-300 dark:bg-gray-600'
+                    step < currentStep ? 'bg-blue-600' : 'bg-gray-300 dark:bg-gray-600'
                   }`}
                 />
               )}