feat(web only): find in chat with mod+f

[imabdulazeez]

What Changed

Adds a find bar over the open thread.

• New chat.find keybinding command, default mod+f with when: "!terminalFocus", plus a "Find in chat" command palette action.
• Matches are counted from the timeline's row model, so messages that the virtualized list has not mounted are still found.
• Matches in mounted rows are painted with the CSS Custom Highlight API. No markdown is rewritten and no DOM nodes are wrapped.
• Enter and Shift+Enter step through matches and scroll each one into view. Esc closes.
• Aa and ab toggles for match case and whole word. One shared pattern feeds both the counter and the highlighter, so counts and painted ranges always agree.
• Selected text becomes the query when the bar opens, as in browser find.
• The pull requests page now resolves the same chat.find command for its list search instead of matching Mod+F by hand.

Composed from the shared UI primitives: InputGroup, InputGroupAddon, InputGroupInput, and InputGroupText for the field, Button (ghost-muted, icon-xs) for the controls, Toggle (ghost, xs) for the options, and the shared keybinding registry via resolveShortcutCommand for the shortcut. No new surfaces or variants are introduced.

Supersedes #5562 with a smaller footprint, and picks up where #4599 left off. Resolves the request in discussion #6709 (formerly #1486).

Why

Long threads have no way to search the conversation. The timeline is virtualized, so the browser's native find only sees mounted rows, and the desktop shell binds no find-in-page at all. Users asked for Codex-style Cmd+F in #1486 and have kept +1ing it since.

Searching the row model rather than the DOM is what makes off-screen matches work. Painting with the Highlight API avoids the code-block corruption that earlier attempts hit when they injected markup into markdown.

Relation to orchestration V2 (#2829)

Earlier find PRs (#3539, #4599, #3779) were closed ahead of the orchestration V2 rewrite. This PR is web-only: it touches no orchestration, adapter, or provider code, and its single server change is one assertion in keybindings.test.ts. Replaying it on the current #2829 head applies cleanly apart from two adjacent-line conflicts in CommandPalette.tsx and keybindings.test.ts, so it should survive that merge with a trivial rebase.

UI Changes

Screen.Recording.2026-09-04.at.3.10.15.PM.mov

Checklist

• This PR is small and focused
• I explained what changed and why
• I included before/after screenshots for any UI changes
• I included a video for animation/interaction changes

Made with Claude Fable 5.1 in Claude Code.

Note

Add chat.find command bound to mod+f for web chat search

• Registers chat.find in the static keybinding registry and maps it to mod+f (excluding terminal focus) in keybindings.ts.
• Adds the ChatFindBar component and search logic in ChatFindBar.logic.ts to find, count, and navigate literal, case-sensitive, and whole-word matches across message rows.
• Renders matches using the CSS Custom Highlight API in chatFindHighlight.ts, and prefills the query from the current browser text selection when it is ≤200 characters.
• Adds a "Find in chat" action to the command palette and updates PullRequestsColumn to open its list search via the resolved chat.find shortcut rather than a hard-coded modifier check.
• Behavioral Change: mod+f outside terminal focus now opens the chat find bar instead of being unhandled in web chat; the pull requests page honors the configured chat.find binding.

^{Macroscope summarized 7e2338a.}

[macroscopeapp]

Approvability

Verdict: Not approved

Macroscope's review found this PR not approvable — This PR adds a substantial find-in-chat workflow across the timeline, command palette, keybinding system, highlighting layer, and pull-request search behavior. It also changes the product default keybindings by assigning mod+f, so the scope and default-behavior change warrant human review.

Notes:

• Macroscope's correctness review did not run, so approvability was decided on eligibility alone.

^{You can add or adjust custom eligibility rules. Learn more.}

[juliusmarminge]

Closing as part of the open-PR backlog sweep (wave 2).

Reason: Superseded by newer fuller find-in-thread #10439
Related: #10439

Reopen if this is still wanted and you’re willing to rebase onto current main.