feat: add model selector, skills/memory pages, and config management

- Add model selector in sidebar that discovers models from auth.json credential pool
- Add per-session model display (badge in chat header and session list)
- Add skills browser page and memory editor page
- Add BFF routes for skills, memory, and config model management
- Model switching updates config.yaml provider field to bypass env auto-detection
- Refactor Settings page, simplify ChatInput with file upload
- Add attachment upload support via BFF /upload endpoint

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "hermes-web-ui",
-  "version": "0.1.3",
+  "version": "0.1.4",
   "description": "Hermes Agent Web UI - Chat and Job Management Dashboard",
   "repository": {
     "type": "git",