feat(branding): migrate hardcoded @brand/logo.png to SVG-aware alias

The four shared layout/login components (Login, LoginDemo,
AppSidebar, MobileDrawer) hardcoded `<img src="@brand/logo.png">`,
which means an SVG-only brand kit (like cfaun's) fails the build
with "Could not load @brand/logo.png".

Switch the four to `<img src="@brand-app-logo">` — the alias registered
via brandAppLogoAliasEntry() (already used by events module) resolves
to whichever of logo.{svg,png} exists in BRAND_DIR (SVG preferred),
with per-app overrides under BRAND_DIR/icons/<app>/.

Also register brandAppLogoAliasEntry in the 8 vite configs that
didn't have it (only events did before), converting their alias maps
to array form so the regex-based logo entry doesn't get shadowed by
the bare-string `@brand` and `@` aliases.

Verified:
- AIO default brand (PNG-only): builds, ships logo-<hash>.png — no regression.
- cfaun brand (SVG-only): builds, ships logo-<hash>.svg — previous
  ENOENT on logo.png gone.

Unblocks cfaun deploy with an SVG-only brand kit (no manual
rasterization needed).

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

vite.chat.config.ts

@@ -5,7 +5,7 @@ import { defineConfig, type Plugin } from 'vite'
 import { VitePWA } from 'vite-plugin-pwa'
 import { ViteImageOptimizer } from 'vite-plugin-image-optimizer'
 import { visualizer } from 'rollup-plugin-visualizer'
-import { brand, brandAlias, brandAssetsPlugin } from './vite-branding'
+import { brand, brandAlias, brandAppLogoAliasEntry, brandAssetsPlugin } from './vite-branding'
 
 function chatHtmlPlugin(): Plugin {
   return {
@@ -103,12 +103,15 @@ export default defineConfig(({ mode }) => ({
       }),
   ],
   resolve: {
-    alias: {
-      ...brandAlias,
+    // Array form so the per-standalone logo regex (matches `@brand-app-logo`
+    // with optional `?url` query) doesn't get shadowed by the bare aliases.
+    alias: [
+      brandAppLogoAliasEntry('chat'),
+      ...Object.entries(brandAlias).map(([find, replacement]) => ({ find, replacement })),
       // ORDER MATTERS — @/app.config must precede @ (first-match-wins).
-      '@/app.config': fileURLToPath(new URL('./src/chat-app/app.config.ts', import.meta.url)),
-      '@': fileURLToPath(new URL('./src', import.meta.url)),
-    },
+      { find: '@/app.config', replacement: fileURLToPath(new URL('./src/chat-app/app.config.ts', import.meta.url)) },
+      { find: '@', replacement: fileURLToPath(new URL('./src', import.meta.url)) },
+    ],
   },
   build: {
     outDir: 'dist-chat',