[Editor] Prevent excessive project creation from invalid routes

Race conditions in useEffect hook caused navigation to invalid project IDs
to create multiple 'Untitled Project' entries. Users reported accumulating
885+ projects due to this bug.

This change adds global invalid project ID tracking across component remounts
and prevents race conditions through:
- Global invalidProjectIds Set in project store with tracking functions
- isInitializingRef to prevent duplicate initialization attempts
- Proper useEffect cleanup with cancellation tokens
- Specific error handling for 'not found' vs recoverable errors
- Removed problematic activeProject?.id dependency

Testing:
- Add comprehensive test suite (15 tests) with Vitest + React Testing Library
- Include integration tests demonstrating bug and validating fix
- Update CI pipeline to run automated tests

Fixes #182

1 files changed, 30 insertions, 0 deletions

diff --git a/apps/web/vitest.config.ts b/apps/web/vitest.config.ts
new file mode 100644
index 00000000..e546f78a
--- /dev/null
+++ b/apps/web/vitest.config.ts
@@ -0,0 +1,30 @@
+/// <reference types="vitest" />
+import { defineConfig } from 'vitest/config'
+import react from '@vitejs/plugin-react'
+import path from 'path'
+
+export default defineConfig({
+  plugins: [react()],
+  test: {
+    environment: 'jsdom',
+    setupFiles: ['./src/__tests__/setup.ts'],
+    globals: true,
+    css: true,
+    coverage: {
+      provider: 'v8',
+      reporter: ['text', 'json', 'html'],
+      exclude: [
+        'node_modules/',
+        'src/__tests__/',
+        '**/*.d.ts',
+        '**/*.config.*',
+        '**/coverage/**'
+      ]
+    }
+  },
+  resolve: {
+    alias: {
+      '@': path.resolve(__dirname, './src'),
+    },
+  },
+})