feat: add username/password login, account settings, and changelog (#133) (#134)

- Add username/password login as additional auth mechanism alongside existing token
- First login must use token; password can be configured in Settings > Account
- Password login returns the existing static token (no auth middleware changes)
- Add account settings: setup, change password, change username, remove password
- Add logout button to sidebar footer
- Add version changelog popup (click version number in sidebar)
- Support all 8 locales (en, zh, de, es, fr, ja, ko, pt)
- Bump version to 0.4.3

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "hermes-web-ui",
-  "version": "0.4.2",
+  "version": "0.4.3",
   "description": "Web dashboard for Hermes Agent — multi-platform AI chat, session management, scheduled jobs, usage analytics & channel configuration (Telegram, Discord, Slack, WhatsApp)",
   "repository": {
     "type": "git",