feat: add eslint, image upload, tests, splash tagline, security hooks

- Restore CLAUDE.md with project conventions
- ESLint config with vue3-recommended + typescript
- Image upload endpoint (POST /api/admin/upload) with 5MB limit
- Admin product form now supports image upload/preview/removal
- Vitest config + 19 tests (crypto, validation, btcpay webhook, types)
- Restore .claude/ security hooks (block-risky-bash, protect-files)
- Logo splash now shows "EVERYTHING YOU LOVE IS A PSYOP" tagline
- Add .vite/ to gitignore

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

vitest.config.ts

@@ -0,0 +1,15 @@
+import { defineConfig } from 'vitest/config'
+import { fileURLToPath, URL } from 'node:url'
+
+export default defineConfig({
+  resolve: {
+    alias: {
+      '@': fileURLToPath(new URL('./src', import.meta.url)),
+      '@shared': fileURLToPath(new URL('./shared', import.meta.url)),
+    },
+  },
+  test: {
+    environment: 'node',
+    include: ['tests/**/*.test.ts'],
+  },
+})