Artifact auto-open is now suppressed for remote-control sessions

Artifact auto-open is now suppressed when the session's messageClientPlatform is ios, android, web_claude_ai, or desktop_app, via a new mode called auto_open_skipped_remote_control. The skipped artifact's slug is recorded in a new remoteControlSkippedSlugs set, and its deferred-surface entry is kept around instead of cleared, so it can retry surfacing later instead of force-opening a browser tab while Claude Code is being driven from a mobile, web, or desktop remote-control client. This path fires unconditionally, with no experiment flag gating it.