Fix ~/database/context resolving to browser stub during dev SSR (#12)

`resolve.alias` with `isSsrBuild` only works at build time — during
`npm run dev`, `isSsrBuild` is always false, so `ssrLoadModule` was
loading the browser stub (DatabaseContext = null) instead of the real
AsyncLocalStorage implementation, causing a TypeError on every request.

Replace the alias with an `enforce: 'pre'` plugin that checks
`options.ssr` at resolve time, which Vite correctly sets for both dev
SSR module loading and production SSR builds.

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

vite.config.ts

@@ -15,20 +15,22 @@ export default defineConfig(({ isSsrBuild }) => ({
         }
       : undefined,
   },
-  resolve: {
+  plugins: [
-    alias: isSsrBuild
+    {
-      ? []
+      name: "database-context-alias",
-      : [
+      enforce: "pre" as const,
-          {
+      resolveId(id, _importer, options) {
-            find: "~/database/context",
+        if (id === "~/database/context") {
-            replacement: path.resolve(
+          return options?.ssr
-              __dirname,
+            ? path.resolve(__dirname, "database/context.ts")
-              "database/context.browser-stub.ts"
+            : path.resolve(__dirname, "database/context.browser-stub.ts");
-            ),
+        }
-          },
+      },
-        ],
+    },
-  },
+    tailwindcss(),
-  plugins: [tailwindcss(), reactRouter(), tsconfigPaths()],
+    reactRouter(),
+    tsconfigPaths(),
+  ],
   server: {
     allowedHosts: true,
   },