feat: improve session resume reliability and persist user settings

- Filter empty sessions from history API (check for conversation content)
- Add --resume fallback to new session if resume fails (prevents dead panes)
- Pass resumeSessionId through respawnPane for dead pane recovery
- Persist respawn presets and runMode to server settings (cross-device sync)
- Fix mobile touch handling for Recent Sessions dropdown (DOM API + touch CSS)

src/session.ts

@@ -912,6 +912,7 @@ export class Session extends EventEmitter {
             claudeMode: this._claudeMode,
             allowedTools: this._allowedTools,
             openCodeConfig: this._openCodeConfig,
+            resumeSessionId: this._resumeSessionId,
           });
           if (!newPid) {
             console.error('[Session] Failed to respawn pane, will create new session');