fix: persist local panels in disconnected remote workspaces

[arzafran]

What this does

Disconnect a remote workspace from the sidebar, keep using it with local shells, and every terminal in it silently vanished from session persistence -- gone at the next restart, with no warning. Three live local terminals were lost this way in a real incident on release 0.4.218: the workspace was absent from both the autosave and the clean-quit snapshot, and there was nothing in the diagnostics log to explain why.

The root cause: remoteConfiguration intentionally survives a user-initiated disconnect (the sidebar's disconnect action passes clearConfiguration: false on purpose, so Reconnect keeps working), but the session-snapshot filter excluded any workspace with remoteConfiguration != nil -- stale config presence, not whether the workspace is actually still live remote right now.

Summary

• Added Workspace.isLiveRemoteWorkspace (isRemoteWorkspace && remoteConnectionState != .disconnected) and switched TabManager.sessionSnapshot to it, so a disconnected-but-configured workspace persists its local panels like any other workspace.
  • Considered clearing remoteConfiguration on disconnect instead (simplest fix): rejected -- reconnectRemoteConnection() and the socket workspace.remote_reconnect path both guard let remoteConfiguration before reconnecting, so clearing it on disconnect would permanently break Reconnect.
  • Considered filtering at the panel level (a connected remote workspace can genuinely contain local panels too, e.g. a split created without an auto-connect startup command) as the most correct long-term shape, but it's a materially larger change to the layout/panel snapshot plumbing. Scoped this fix to the reported incident (a fully disconnected workspace) and called the mixed-panel-while-connected gap out below rather than guessing at a bigger restructure.
• Every workspace still skipped for being genuinely live-remote now logs session.snapshot skipped workspace=<id> reason=remote panels=<n> to the always-on diagnostics log (~/Library/Logs/Programa/diagnostics.log), so this class of gap is never silent again.
• TerminalController+Telemetry's TTY-report/port-kick routing had the same stale-flag bug (a disconnected-but-configured workspace's local panels stopped getting local port-scanning/dev-server detection, since telemetry kept routing to an inert remote path) -- switched those 4 branches to isLiveRemoteWorkspace too.
• Left other isRemoteWorkspace call sites (sidebar Reconnect/Disconnect menu state, browser proxy website-data-store routing, git-metadata-polling exclusion) untouched -- those gate "has a remote destination configured" facts, not the live-session distinction this bug is about.

Known residual gap (disclosed, not fixed here): a workspace that is still actively connected but also contains local panels (possible when a split is created without an auto-connect startup command) still has those local panels excluded from persistence, same as before. It's no longer silent -- the new diagnostics line fires for it too -- but a full fix needs panel-level filtering in the layout snapshot, which is a larger, separate change.

Test Plan

• xcodebuild -project GhosttyTabs.xcodeproj -scheme programa -configuration Debug -destination 'platform=macOS' -derivedDataPath /tmp/programa-remotefix build -> BUILD SUCCEEDED
• Two-commit red/green: commit 1 (test only) fails with 3 assertion failures against unmodified source; commit 2 (fix) passes
• -only-testing:programaTests/WorkspaceRemoteConnectionTests -> 41/41 passed
• -only-testing:programaTests/TabManagerSessionSnapshotTests -> 3/3 passed (existing exclusion test updated to simulate an actually-connected workspace, since it previously relied on the buggy "config present = excluded" behavior)
• -only-testing:programaTests/SessionPersistenceTests -> 62/62 passed
• -only-testing:programaTests/TerminalControllerSocketSecurityTests -> 11/11 passed

[arzafran]

Residual edge worth tracking separately (not blocking): isLiveRemoteWorkspace treats .error as live, so a workspace whose remote connection errored and was never explicitly disconnected stays excluded from snapshots — the same data-loss shape as this bug, with a narrower trigger. It now at least logs via the new session.snapshot line instead of being silent. Worth deciding whether .error should decay to .disconnected after a timeout, or be treated as not-live for persistence purposes.