Fix Cloud composer pane focus convergence

[azooz2003-bit]

Summary

When a Cloud terminal and a local terminal share a workspace, the Cloud composer can receive keyboard focus while the focus ring stays on the local pane during a SwiftUI host callback rebind. Composer focus now selects its live owning pane directly and preserves the composer as first responder. Background workspace callbacks cannot change selection.

This covers the composer path alongside the terminal input fix in #16271 and the middle-click fix in #16513.

Testing

• Swift syntax check passed for all three changed files.
• Test wiring and git diff --check passed.
• Added regressions for mixed local/Cloud composer focus, draft and responder preservation through a run-loop turn, and background workspace selection. Native tests and live app verification have not run.
• No new user-facing strings.

Changelog

Fixed: Focusing a Cloud terminal's text box also moves the pane focus ring to Cloud.

Demo Video

No live capture; the regression exercises AppKit composer focus without the SwiftUI host callback.

Checklist

• Behavior changes have added or updated tests
• Localization audited; no user-facing strings added

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Summary by cubic

Fixes Cloud composer focus convergence so the pane focus ring follows the keyboard target when a Cloud terminal shares a workspace with a local one.

• Composer focus now resolves its live owning pane directly and keeps the composer as first responder, instead of relying on a SwiftUI host callback that can be mid-rebind.
• Routes selection through the workspace coordinator with a standard trigger so no terminal first-responder follow-up steals focus back from the text box; wires the new onFocusTextBox callback through docked, hosted, and remote tmux panels.
• Background workspace callbacks can no longer change pane selection.
• Adds regression tests that exercise the production composer callback for mixed local/Cloud focus, draft and responder preservation through a run-loop turn, and background workspace selection.

^{Written for commit babb42f. Summary will update on new commits.}

Summary by CodeRabbit

• Bug Fixes
  • Focusing a panel’s text box now selects the corresponding pane and keeps the text box ready for input, including in docked and hosted panels.
  • Cloud composer drafts are preserved when focusing the text box.
  • Focusing a Cloud composer in a background workspace no longer changes the selected workspace or source panel.
  • Text-box focus now activates the appropriate pane in remote tmux views as well.

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Migrated from #16704 after correcting the PR author identity. The original head commit babb42f is preserved.

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📥 Commits

Reviewing files that changed from the base of the PR and between ccefb63 and babb42f.

📒 Files selected for processing (11)

• Sources/Canvas/CanvasHostedPanelContentView.swift
• Sources/DockSplitPanelContentView.swift
• Sources/Panels/PanelContentView.swift
• Sources/Panels/TerminalPanelView.swift
• Sources/RemoteTmuxWindowMirrorSplitView.swift
• Sources/Workspace.swift
• Sources/WorkspaceContentView.swift
• cmuxTests/BrowserPanelViewIdentityTests.swift
• cmuxTests/BrowserPanelWindowVisibilityTests.swift
• cmuxTests/SimulatorPanelThemeTests.swift
• cmuxTests/SurfacePaneFactoryFocusTests.swift

• Autopilot · Keep fixing CodeRabbit findings and required CI, and resolving merge conflicts

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[github-actions]

Note

Pull Request opener @azooz2003-bit is not an author or co-author of any commit in this PR (commit identities: teamleaderleo). The CLA check will still proceed and requires every listed identity plus @azooz2003-bit to have signed.

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[github-actions]

Dogfood tours of babb42fc

sidebar-and-chrome-tour at babb42fc: not run

skipped: CI built this head on a runner pool whose products the UI test Macs cannot load, and media never compiles one; gh workflow run pr-media.yml -f pr=<n> -f allow_compile=true does

_{Tours are picked by the paths globs in dogfood/scenarios/*.json; a Dogfood-tours: a, b line in the description picks them instead (none turns this off). Look at every frame before merging: a green tour only means no step failed.}