Keep command-palette guidance visible while navigating

[brsbl]

Rebased head 68c157fdf has passing remote CI. Fresh screenshots below compare current origin/main (4ed274321) with this exact head and include the exact parent/merge-base baseline. Nothing merged.

What was wrong

Keyboard guidance disappeared or detached from the result viewport. Dialog-level clipping also cut off the scope menu on short result lists, so clicking the clipped Archived option could dismiss the palette.

What changed

• Keep a persistent shared palette shell and footer, with consistent Back guidance, scrolling boundaries, grouped commands, and drill-in treatment.
• Move clipping to the result viewport; keep the scope menu outside dialog clipping while preserving rounded input/footer edges.
• Preserve command execution, destinations, thread search, and the parent's archived-split fix.
• Add focused shell, scope-menu pointer-selection, and Plugin Guide source-anchor coverage.

Startup-size allowance

Increase only the raw maxBootBytes budget by 2,048 bytes (about 0.12%), from 1,723,617 to 1,725,665, for the persistent shell/guidance. The synchronized main budget was exceeded by 1.3 KiB at this layer and 1.6 KiB at the hierarchy layer. The 419.0 KiB compressed budget, forbidden dependency gates, and route-closure budgets remain unchanged. Final-head CI passes the budget checks.

No public or wire contracts changed. Lower-priority prototype/abstraction cleanup remains follow-up work, not an additional review-driven expansion.

Screenshots

Captured 2026-09-09 in the isolated branch web app, Chrome for Testing 153.0.8010.36, light theme, 1440×900 at DPR 1. Same dev database, synthetic archived reference, installed plugins, and /settings/keyboard route throughout.

• Thread search: Command-K, query “Archived design reference”, first result selected.
• Commands: Command-Shift-P, unfiltered command list at the top. Main's “>” prefix and the branch's empty query are their native shortcut behavior.
• origin/main advanced to 4ed274321 after the rebase onto 0b4115aa9; current-main comparison is intentionally separate from the exact layer baseline.

Current origin/main versus this PR

State	Before — current main 4ed274321	After — exact PR head 68c157fdf
Thread search
Commands

Exact layer baseline — 60f481e2a

These are the matching before images from the parent PR head. The exact-head images above are the after images for this layer.

Thread search — before	Commands — before

Historical evidence from before the rebase

The following captures retain their original source revisions. They document earlier implementation and bug verification, not the current PR head.

Exact branch web app, same synthetic threads, active-thread route, query “Archived design reference”, light theme, and 1440×900 viewport in Chrome for Testing 153.0.8010.36.

Before — exact parent head b875f102b

After — reviewed pre-rebase head aabc9dd13

After — entire scope menu remains visible on a one-result list

Historical bug evidence — pre-fix 539a14ef5

This earlier capture uses the prior “Palette unsent draft” fixture on Keyboard settings. It demonstrates the original clipping; it is not the paired exact-parent comparison above.

How you verified

• Fresh exact-revision visual evidence captured and inspected for thread search and the root command list, including opening, settled rendering, and Escape between modes. This was a bounded evidence refresh, not a repeated full QA pass. No product code changed.
• Pre-rebase remote CI passed checks, app/server/package/integration tests, contributor/version checks, and Linux/macOS package smoke. Workflow-configured iOS/Node Compatibility skips only. No local tests, typechecks, or lint.
• Bounded Chrome for Testing 153.0.8010.36 pass verified a one-result scope menu, pointer selection of Archived below the dialog edge without dismissal, input focus restoration, Escape back/close, hard reload, and command navigation to Keyboard settings. No browser errors during that pass.
• Parent's archived-split fix also verified in the real integrated app, through reload and the source CLI. Fresh exact parent/head visual evidence above.
• Cumulative review completed; both P1 fixes are resolved in their originating layers. No second review. The pre-rebase head was CLEAN and MERGEABLE. Nothing merged.

BB-Thread-ID: thr_ccffp4w2p2

AGENT GENERATED

[brsbl]

Superseded by #3370, which now contains the complete final UI diff directly on the functionality foundation. The final source head remains 75de5eb; this consolidation changes no product code. Discussion, commits, and the branch are preserved here. Nothing was merged.