chore(dev): pin standalone ports + add dev:all script

Fixed-port assignments for each standalone vite dev server, with
strictPort to fail loud if a port is taken (no silent +1 increment
that would break the hub's hardcoded VITE_HUB_<NAME>_URL targets):

  hub        5173  (npm run dev)
  castle     5180
  sortir     5181  (activities)
  wallet     5182
  chat       5183
  forum      5184
  market     5185
  tasks      5186

`npm run dev:all` boots the hub and all 7 standalones concurrently
via the existing concurrently devDep. The hub's chakra tiles point
at these ports via VITE_HUB_<NAME>_URL in .env.local for end-to-end
local testing of the cross-subdomain auth relay.

Pure dev infrastructure — no production behaviour change.

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

vite.forum.config.ts

@@ -35,6 +35,10 @@ function forumHtmlPlugin(): Plugin {
  */
 export default defineConfig(({ mode }) => ({
   base: process.env.VITE_BASE_PATH || '/',
+  server: {
+    port: 5184,
+    strictPort: true,
+  },
   plugins: [
     forumHtmlPlugin(),
     vue(),