Land the Repository pane hosting History and Pull Requests as its own branch

[Defmon3]

Seen on: work/stack-6315-refresh-20260829

What it fixes

After the History and Pull Requests tabs exist, they are two more tabs in an already crowded right panel, and each forgets nothing or everything on its own terms. This piece folds them into one Repository tab with History and Pull Requests as sub-tabs, keeping each sub-tab's search, selection, and paging across switches, all scoped to the project and environment.

Why we need it

It is PR 10 of the series in the Git History series issue (#8). It is the pane the end state describes, minus the one tab that waits on upstream.

How to fix it

Cut a fresh branch on top of the History and Pull Requests tab pieces carrying the Repository pane, the right-panel surface rename and persisted-state migration, and the state-keeping across sub-tab switches, with tests. The PR description states the end state from the series issue. Deferred: the Issues sub-tab.

[Defmon3]

Technical appendix: Land the Repository pane hosting History and Pull Requests as its own branch

Investigated on branch work/stack-6315-refresh-20260829 at commit 23578f462. Findings marked "verified" were confirmed by an independent review pass on 2026-09-04.

Findings

• apps/web/src/components/RepositoryPanel.tsx (new, about 280 lines): the pane with three modes, rendered from ChatView.tsx inside the thread's right panel with the active project's id, keyed by thread and project so a project switch remounts it. Verified.
• History is kept mounted across sub-tab switches through Activity; Issues and Pull Requests render behind plain mode guards and unmount on switch, so their search, filters, and paging, which live in component state, are lost. Verified.
• apps/web/src/rightPanelStore.ts (+118) and apps/web/src/components/RightPanelTabs.tsx (+39): the persisted right-panel state version moves from 13 to 15 with a migration for the surface's view state. Verified. The surface id stays git-history in the store and in persisted state while the tab title, launcher entry, and component say Repository.
• apps/web/src/components/ChatView.tsx (+141) and ChatView.logic.ts (+21): the pane wiring. handleIssueTabStatusChange and handlePullRequestTabStatusChange return early unless a matching issue or pull request surface is active, so the status callbacks passed to RepositoryPanel never fire. repositoryAvailable and the Repository launcher action test for a repository in two different ways.
• Existing routes are untouched; the standalone Issues and Pull Requests pages keep working. Verified.
• Size: about 600 source lines plus tests.

The problem

Observed: History and Pull Requests would be separate right-panel tabs, and the only unified pane exists on a fork branch with the defects above.

Once done: one Repository tab hosts History and Pull Requests as sub-tabs, each keeps its state across switches, persisted panel state migrates cleanly, and the surface is named the same in code and in the UI.