Add build-time config stub via Vite plugin

During `vite build`, env vars are unavailable so the real config
validation fails. A Vite plugin now redirects all imports of
$lib/config to a build-stub with safe defaults.

Author: max-lt

src/lib/config/build-stub.ts

@@ -0,0 +1,35 @@
+/**
+ * Build-time stub for $lib/config.
+ * During `vite build`, env vars are unavailable — this provides safe defaults
+ * so that module-level imports don't throw. None of this code runs at runtime.
+ */
+import type { Config, Environment } from './index';
+
+const nodeEnv: Environment = 'development';
+const port = 7000;
+
+const jwt = { access: { secret: '-' }, refresh: { secret: '-' } };
+const github = {};
+const postgate = { url: '-', token: '-', systemTokenSecret: '-' };
+const sharedStorage = {};
+const email = {};
+const mistral = {};
+const anthropic = {};
+
+const appUrl = 'http://localhost:4200';
+
+export const config: Config = {
+  nodeEnv,
+  port,
+  jwt,
+  github,
+  postgate,
+  sharedStorage,
+  mistral,
+  anthropic,
+  email,
+  appUrl
+} as Config;
+
+export { nodeEnv, port, jwt, github, postgate, sharedStorage, mistral, anthropic, email, appUrl };
+export type { Config, Environment };

src/lib/config/index.ts

@@ -182,7 +182,7 @@ function loadConfig(): Config {
 }
 
 // Export singleton config instance
-export const config = loadConfig();
+export const config: Config = loadConfig();
 
 // Export individual sections for convenience
 export const { nodeEnv, port, jwt, github, postgate, sharedStorage, mistral, anthropic, email, appUrl } = config;

vite.config.ts

@@ -84,8 +84,41 @@ if (!/^\d{1,5}$/.test(envPort || '')) {
   console.warn(`Warning: Invalid PORT environment variable "${envPort}", defaulting to 5173`);
 }
 
+/**
+ * At build time, replace $lib/config with a stub that provides safe defaults.
+ * Env vars are unavailable during `vite build` — the real config loads at runtime.
+ */
+function configBuildStubPlugin(): Plugin {
+  const stubPath = resolve('./src/lib/config/build-stub.ts');
+  const realConfigPath = resolve('./src/lib/config/index.ts');
+  let isBuild = false;
+
+  return {
+    name: 'config-build-stub',
+    enforce: 'pre',
+
+    configResolved(config) {
+      isBuild = config.command === 'build';
+    },
+
+    async resolveId(id, importer, options) {
+      if (!isBuild) return;
+
+      // Don't redirect the stub's own type import back to itself
+      if (importer === stubPath) return;
+
+      // Let Vite resolve normally, then check if it points to config/index.ts
+      const resolved = await this.resolve(id, importer, { ...options, skipSelf: true });
+
+      if (resolved && resolved.id === realConfigPath) {
+        return stubPath;
+      }
+    }
+  };
+}
+
 export default defineConfig({
-  plugins: [cronerWasmInlinePlugin(), zodLocalesPlugin(), sveltekit()],
+  plugins: [configBuildStubPlugin(), cronerWasmInlinePlugin(), zodLocalesPlugin(), sveltekit()],
   server: {
     port: parseInt(process.env.PORT || '5173', 10)
   }