Echo Chamber v0.6.8

• Fix native screen-share restart churn: stop commands now wait for the previous native capture task to exit before a new $screen publisher connects
• Fix viewer native stop-listener cleanup so repeated restarts do not stack duplicate listeners
• Fix remote screen-share watching after reconnect/reload by normalizing $screen companion identities consistently across late join, watch/unwatch, and adaptive stats paths
• Fix Start Watching for remote screen shares so existing live shares attach correctly instead of staying hidden or unsubscribed
• Fix the false "New Version Available" banner when running prerelease-style local builds
• Win10 picker now blocks unsupported native Windows capture entries and directs users to Screen/Game
• Native pipeline now includes the WGC heartbeat/static-frame duplication fix and keeps native publish pacing aligned to the 30fps target