Open palette search results in splits - #3595

Human comments

What was wrong

Thread search results could only replace the current view; users could not open a result beside their existing thread.

What changed

• Open selected results in splits with Command/Control-Enter or the labeled “Open in split” row action.
• Preserve message-match anchors when opening a split.
• Group status with project metadata; reserve the right side for the selected-row action, without a footer hint.

How you verified

• Head 1fdbcae3b: CI blocked by workspace-download timeout; the app-1 shard did not reach tests.
• Chrome for Testing 153: the selected result opens beside the current thread; the parent replaces the current view.
• Desktop and phone captures confirm status beside project metadata. Previously reviewed behavior; no additional code review.

Desktop comparison

Fresh pixels from the exact source web app revisions below, using the same fixtures, route, selection and CSS viewport at 2× density. Desktop: 1440×900 CSS / 2880×1800 PNG. Phone: 390×844 CSS / 780×1688 PNG.

State	Before — #3370 15e439bec	After — 1fdbcae3b
Search threads · before typing
Search threads · title, follow-up draft, archived and message results
Search threads · message match

State	Before — #3370 — replaces current view	After — #3595 — opens beside current view
Command-Enter on the selected thread result

Phone comparison

State	Before — #3370 15e439bec	After — 1fdbcae3b
Search threads · before typing
Search threads · title, follow-up draft, archived and message results
Search threads · message match

The pencil marks an existing thread with an unsent follow-up, not a first-class saved draft resource. Message screenshots verify result rendering, not message-anchor landing. This PR remains draft while exact-head CI is incomplete.

BB-Thread-ID: thr_82jtfaq8eq

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