## Summary

- The commit message editor in the Git panel is pinned to six lines and
its only two controls both make it *larger* — one fills the panel, the
other opens the modal. Anyone who commits from a terminal pays for an
input they never use, and the Changes list is what gets squeezed.
- In the Git Graph detail panel, the author metadata and the commit
message render at a fixed size above the changed-files list, so
shortening the panel (e.g. dragging the terminal up) hides the file list
entirely.

## Changes

**Git panel — collapsible commit editor**

- New `git::ToggleCommitEditor` action.
- A chevron beside the commit button hides the editor down to a thin
bar; the commit button row stays available.
- State persists per workspace via `SerializedGitPanel`, seeded from a
new `git_panel.commit_editor` setting (`expanded` | `collapsed`, default
`expanded`).
- Collapsing clears the fill state — a hidden editor cannot also fill
the panel.
- `activation_focus_handle` no longer focuses an editor that isn't
rendered.

**Git Graph — collapsible commit details**

- A disclosure folds the author metadata (avatar, refs, email, SHA,
provider link) down to a single author + short-sha line.
- A second disclosure folds the commit message body.
- The changed-files container is already `flex_1().min_h_0()`, so it
reclaims the freed space with no other layout change.

**Settings plumbing**

- `GitPanelCommitEditor` in `settings_content`, wired through
`GitPanelSettings`, `assets/settings/default.json`, the settings UI, and
`docs/src/reference/all-settings.md`.

## Test plan

- [x] `test_toggle_commit_editor_collapsed` added, covering the toggle,
persistence of the flag, and the fill/collapse exclusion.
- [x] Manually verified in a dev build: chevron hides and restores the
editor, Changes list expands into the freed space, action appears in the
command palette, state survives a restart, and the `collapsed` setting
seeds a new workspace.
- [x] Manually verified both disclosures in the Git Graph detail panel
with the panel shortened, including that the collapse state survives
selecting a different commit.

Release Notes:

- Improved the Git panel by allowing the commit message editor to be
collapsed, and the Git Graph commit details by making the metadata and
commit message sections collapsible.

### Evidance Test
| Expand | Collapse | Settings Git Panel |
| ------- | --------- | ------------------ |
| <img width="675" height="965" alt="Screenshot 2026-08-26 at 15 00 46"
src="https://github.com/user-attachments/assets/70c56d02-35fc-45ac-988c-24ccd6d1a19e"
/> | <img width="661" height="962" alt="Screenshot 2026-08-26 at 15 00
57"
src="https://github.com/user-attachments/assets/2c32fa5d-30fc-4f35-8323-afbc2a031210"
/> | <img width="1041" height="956" alt="Screenshot 2026-08-26 at 16 50
40"
src="https://github.com/user-attachments/assets/67f166b6-5cd9-4430-bba3-fa765715c557"
/> |

---------

Co-authored-by: Christopher Biscardi <chris@christopherbiscardi.com>