fix: use configured cooldown as cap for rate limit wait times

- Cooldown now caps API-provided reset times instead of being a fallback
- Fixed misleading UI descriptions for cooldown settings
- Removed unused cooldownDurationMs from settings object
- Updated default fallback values in frontend to 10s

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

src/account-manager/index.js

@@ -191,7 +191,7 @@ export class AccountManager {
      * @param {string} [modelId] - Optional model ID to mark specific limit
      */
     markRateLimited(email, resetMs = null, modelId = null) {
-        markLimited(this.#accounts, email, resetMs, this.#settings, modelId);
+        markLimited(this.#accounts, email, resetMs, modelId);
         this.saveToDisk();
     }