[coneilen]

Summary

Finish the remaining source-backed Windows loop-workspace chrome gaps by showing the focused agent pane's backend identity and matching macOS control order across paint, pointer routing, and UI Automation. This remains a source/test slice; it does not establish full issue #772 visual or live-session acceptance.

Changes

• Show lowercased backend detail such as copilot cli at the trailing edge of a focused agent pane header.
• Order the workspace controls as Split Right, Split Down, New Tab and derive UIA identity/labels from the same production action mapping.
• Retarget adjacent native workspace tests and assert that Split Right produces a horizontal split.

Test plan

RED: D:\gct\w772\zig-0.15.2\zig.exe test src\TerminalSurface.zig -target x86_64-windows-msvc -lc -luser32 -lgdi32 -ladvapi32 -ID:\gcp\w772\winghostty\include D:\depot\copilot-worktrees\GraphCode\coneilen-ideal-pancake\graphcode-windows\zig-out\lib\ghostty-vt-static.lib --test-filter "issue 772" -> 1/1 failed: expected .split_right, found .new_tab
GREEN: D:\gct\w772\zig-0.15.2\zig.exe test src\TerminalSurface.zig -target x86_64-windows-msvc -lc -luser32 -lgdi32 -ladvapi32 -ID:\gcp\w772\winghostty\include D:\depot\copilot-worktrees\GraphCode\coneilen-ideal-pancake\graphcode-windows\zig-out\lib\ghostty-vt-static.lib --test-filter "issue 772" -> All 1 tests passed
REGRESSION: D:\gct\w772\zig-0.15.2\zig.exe test src\TerminalSurface.zig -target x86_64-windows-msvc -lc -luser32 -lgdi32 -ladvapi32 -ID:\gcp\w772\winghostty\include D:\depot\copilot-worktrees\GraphCode\coneilen-ideal-pancake\graphcode-windows\zig-out\lib\ghostty-vt-static.lib -> All 291 tests passed

Additional verification:

• Focused App UIA order test -> All 1 tests passed.
• Focused native New Tab tests -> All 6 tests passed.
• Focused native Split Right orientation test -> All 1 tests passed.
• Full App regression -> 1418 passed; 17 skipped; 0 failed.
• Independent review found no remaining significant issues after the UIA/action-order fixes.

Not verified / NotExecuted:

• Real daemon-backed Restart execution, remount continuity, and resulting terminal state.
• Live multi-tab, multi-split, focus, close, overflow, and backend combinations.
• Paired current Windows and macOS screenshots or visual review; source-only work cannot validate the whole issue.
• Native keyboard input, glyph rendering, accessibility conformance, or pixel-level parity.

Refs #772

Checklist

• I have read the Contributing Guidelines
• I have signed off my commits (git commit -s) per the DCO
• Tests pass locally (make test)
• Code follows the existing style (make check)
• I added the test/contract before the implementation and observed the intended RED failure

Windows-scoped pinned Zig tests are listed above. The macOS-only make test and make check commands were not run.