* gui: improve workspace hierarchy and pane focus treatment

* gui: streamline worktree actions and explain disabled controls

* docs: capture subtle hierarchy and worktree action conventions

* docs: wrap worktree interaction guidance

* gui: keep worktree branch borrowed while building action hints

* gui: give task board headings a quiet count badge

* gui: style stage counters using semantic Adwaita surfaces

* test(gui): assert task board stage labels and count badges together

* docs: describe t3code-inspired task board stage counters

* gui: apply rustfmt layout to visual polish changes

* gui: apply rustfmt layout to visual polish changes

* gui: apply rustfmt layout to visual polish changes

* test(gui): read the Done count from the stage counter badge

task_board_explains_truncated_done_history still looked for the old
"Done · N" heading text, which the new heading/count badge split
removed, so the GTK test failed.

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Co-authored-by: Grok Bot <grok-bot@users.noreply.github.com>