feat(10.1-02): run registered toolbar actions and scope plugin CSS per controller

- ListToolbar renders server-filtered actions after delete as outline buttons, busy during their POST
- ListView posts {} to toolbar/{action}, toasts, reloads the list and refetches the header partial
- Lists load controller assets too, so other controllers' stylesheet links are disabled on every open
- Vite dev server proxies {prefix}/assets to summer serve; dist rebuilt

admin/vite.config.ts

@@ -5,8 +5,8 @@ import tailwindcss from '@tailwindcss/vite'
 // The committed build is path-agnostic (D-02): assets use a relative base and
 // index.html keeps the __SUMMER_ADMIN_BASE__ token, which the Go server
 // (boardwalk) replaces with the configured backend.uri. The dev server
-// replaces it with SUMMER_ADMIN_DEV_PREFIX and proxies the admin API to a
-// running `summer serve` at SUMMER_ADMIN_DEV_TARGET.
+// replaces it with SUMMER_ADMIN_DEV_PREFIX and proxies the admin API and the
+// plugin assets to a running `summer serve` at SUMMER_ADMIN_DEV_TARGET.
 const devPrefix = (process.env.SUMMER_ADMIN_DEV_PREFIX ?? '/backend').replace(/\/+$/, '')
 const devTarget = process.env.SUMMER_ADMIN_DEV_TARGET ?? 'http://localhost:8080'
 
@@ -29,6 +29,8 @@ export default defineConfig(({ command }) => ({
   server: {
     proxy: {
       [`${devPrefix}/api`]: { target: devTarget, changeOrigin: false },
+      // Plugin JS/CSS that controllers declare (Phase 10.1), served by cabana.
+      [`${devPrefix}/assets`]: { target: devTarget, changeOrigin: false },
     },
   },
 }))