Land a plain History tab for the current branch as its own branch

[Defmon3]

Seen on: component/git-history

What it fixes

With the server reads in, users still see nothing. This piece adds a History tab to the thread's right panel with a plain commit list for the current branch: subject, author, date, refs, load more, refresh, and a plain message on servers that do not support history yet. No graph, no details pane, no branches pane, no diff.

Why we need it

It is PR 4 of the series in the Git History series issue (#8) and the first one a user can see. A small visible surface lets maintainers judge the look and the performance rules before the larger pieces arrive.

How to fix it

Cut a fresh branch on top of the server pieces carrying the panel shell, the virtualized commit list without graph lanes, the history query and cache keys, the right-panel wiring, the client-side cache invalidation that fires on repository mutation even while the tab is closed, and the user docs entry. The timestamp defect is fixed in this piece. The PR description states the end state from the series issue. Deferred: the graph, the details pane, the branches pane, favorites, and the diff view.

[Defmon3]

Technical appendix: Land a plain History tab for the current branch as its own branch

Investigated on branch component/git-history at commit 821fc7f, base upstream/main at a6797b3.

Findings: what exists today

• apps/web/src/components/GitHistoryPanel.tsx (820 lines, new): component GitHistoryPanel holds the header, the layout hook, the commit list, the details pane, the refs pane, the resize handles, and the narrow-layout sheets in one file. It imports GitRefsPane, useGitHistoryRefs, GitHistoryCommitDetails, GitHistoryCommitDiff, and GitHistoryPaneResizeHandle, so today it cannot render without them.
• apps/web/src/components/git-history/GitHistoryCommitList.tsx (366 lines, new): the virtualized list through LegendList, the row with graph lanes drawn from layoutGitHistoryGraph, the copy-hash button, and formatCommitDate.
• apps/web/src/state/queries.ts (+169): the history query atoms, usePaginatedHistoryRefs, useDebouncedValue, and the cache keys; query.ts, vcs.ts, paginatedBranches.ts small changes. queries.test.tsx (new).
• apps/web/src/gitHistoryCapability.ts (new): hasGitHistoryCapability.
• apps/web/src/rightPanelStore.ts (+4) and apps/web/src/components/RightPanelTabs.tsx (+30): the git-history right-panel surface. apps/web/src/components/ChatView.tsx (+30): mounts the panel with the active project's repository path.
• packages/client-runtime/src/state/vcsRefInvalidation.ts: historyRevisionByRepository, an Atom.keepAlive family bumped on repository mutation; vcs.ts wiring. Tests alongside.
• apps/web/src/test/reactHookHarness.ts (+18), docs/user/source-control.md (+13).

Estimated size of this piece once the graph, details, refs, sheets, and diff code are left to later pieces: about 900 source lines.

Findings: behavior established by reading

• The history revision atom family is keepAlive, so a mutation made while the panel is closed still invalidates cached history.
• The panel does not fold the connection generation into its target key, so a reconnect does not clear the search box or the selected commit.
• The commit list and refs pane render through LegendList with an estimated item size; history is capped at ten pages of 100 commits.
• formatCommitDate pins 24-hour time; see the issue "Commit dates in Git History ignore the timestamp setting".

Findings: test state

• apps/web/src/components/GitHistoryPanel.test.tsx passes on this branch (run 2026-09-04).

The problem

Observed: the panel exists only as one file that also contains the graph, details, refs, sheets, and diff code.

Once done: a branch on top of the server pieces adds a History tab that lists the current branch's commits with load more and refresh, shows a capability message on an older server, invalidates on repository mutation even while closed, and formats dates by the timestamp setting.