fix(plugin): respect Vite base path in script injection and SW URL

The plugin was emitting a hardcoded "/@id/virtual:twd/init" script
tag in transformIndexHtml(), which 404s on dev servers configured
with a non-root base (e.g. base: "/platform-admin/") because Vite
serves all dev resources under that prefix.

Capture the resolved base via configResolved() and prefix:
  - script src in transformIndexHtml — always
  - default serviceWorkerUrl — only when the user did NOT explicitly
    set it (so user-supplied paths like "/platform-admin/mock-sw.js"
    are not double-prefixed)

Default base "/" preserves existing behavior. Tests cover all four
combinations (base x serviceWorkerUrl override).

Reported by a real-project consumer with:
  base: "/platform-admin/"
  → GET http://localhost:5173/@id/virtual:twd/init 404

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: kevinccbsg

src/plugin/twd.ts

@@ -1,4 +1,4 @@
-import type { Plugin } from 'vite';
+import type { Plugin, ResolvedConfig } from 'vite';
 import type { TWDTheme } from '../ui/utils/theme';
 
 /**
@@ -99,11 +99,28 @@ const DEFAULT_INIT_OPTIONS = {
  */
 export function twd(options: TwdPluginOptions = {}): Plugin {
   const { testFilePattern = DEFAULT_PATTERN, ...userInitOptions } = options;
+  // Track whether the user explicitly set serviceWorkerUrl so we don't
+  // double-prefix when applying the resolved Vite base path.
+  const userSetServiceWorkerUrl = userInitOptions.serviceWorkerUrl !== undefined;
   const initOptions = { ...DEFAULT_INIT_OPTIONS, ...userInitOptions };
 
+  // Captured from configResolved. Vite normalizes this to start and end
+  // with "/" (default "/"). Used to prefix dev-server-relative URLs so
+  // the plugin works under non-root `base` configs (e.g. "/platform-admin/").
+  let resolvedBase = '/';
+
   return {
     name: 'twd',
     apply: 'serve',
+    configResolved(config: ResolvedConfig) {
+      resolvedBase = config.base;
+      // If the user didn't override serviceWorkerUrl, prefix the default
+      // with the resolved base so the SW resolves under non-root deployments.
+      if (!userSetServiceWorkerUrl && resolvedBase !== '/') {
+        const trimmed = DEFAULT_INIT_OPTIONS.serviceWorkerUrl.replace(/^\//, '');
+        initOptions.serviceWorkerUrl = `${resolvedBase}${trimmed}`;
+      }
+    },
     resolveId(id) {
       if (id === VIRTUAL_ID) {
         return RESOLVED_VIRTUAL_ID;
@@ -124,7 +141,7 @@ export function twd(options: TwdPluginOptions = {}): Plugin {
       return [
         {
           tag: 'script',
-          attrs: { type: 'module', src: `/@id/${VIRTUAL_ID}` },
+          attrs: { type: 'module', src: `${resolvedBase}@id/${VIRTUAL_ID}` },
           injectTo: 'head' as const,
         },
       ];

src/tests/plugin/twd.spec.ts

@@ -88,5 +88,51 @@ describe('twd vite plugin', () => {
         },
       ]);
     });
+
+    it('prefixes the script src with a non-root resolved base', () => {
+      const plugin = twd();
+      const configResolved = plugin.configResolved as (config: { base: string }) => void;
+      configResolved.call({}, { base: '/platform-admin/' });
+      const transform = plugin.transformIndexHtml as () => unknown;
+      const result = transform.call({});
+      expect(result).toEqual([
+        {
+          tag: 'script',
+          attrs: { type: 'module', src: '/platform-admin/@id/virtual:twd/init' },
+          injectTo: 'head',
+        },
+      ]);
+    });
+  });
+
+  describe('base path handling for serviceWorkerUrl', () => {
+    it('prefixes the default serviceWorkerUrl with a non-root base', () => {
+      const plugin = twd();
+      const configResolved = plugin.configResolved as (config: { base: string }) => void;
+      configResolved.call({}, { base: '/platform-admin/' });
+      const load = plugin.load as (id: string) => string | null;
+      const code = load.call({}, '\0virtual:twd/init');
+      expect(code).toContain(`"serviceWorkerUrl":"/platform-admin/mock-sw.js"`);
+    });
+
+    it('leaves the default serviceWorkerUrl unchanged when base is "/"', () => {
+      const plugin = twd();
+      const configResolved = plugin.configResolved as (config: { base: string }) => void;
+      configResolved.call({}, { base: '/' });
+      const load = plugin.load as (id: string) => string | null;
+      const code = load.call({}, '\0virtual:twd/init');
+      expect(code).toContain(`"serviceWorkerUrl":"/mock-sw.js"`);
+    });
+
+    it('preserves a user-supplied serviceWorkerUrl regardless of base', () => {
+      const plugin = twd({ serviceWorkerUrl: '/custom/path/mock-sw.js' });
+      const configResolved = plugin.configResolved as (config: { base: string }) => void;
+      configResolved.call({}, { base: '/platform-admin/' });
+      const load = plugin.load as (id: string) => string | null;
+      const code = load.call({}, '\0virtual:twd/init');
+      // Not double-prefixed — user-supplied value wins.
+      expect(code).toContain(`"serviceWorkerUrl":"/custom/path/mock-sw.js"`);
+      expect(code).not.toContain(`/platform-admin/custom`);
+    });
   });
 });