Browser Search: add an explicit close control distinct from clearing the query #294

Parent plan: #286.

User request and observed behavior

P2 small interaction improvement. The user supplied an ArcZip search screenshot with a trailing close button and requested the equivalent in Stow. A screenshot establishes the control's appearance; native ArcZip 1.2.1 (336) inspection additionally confirmed that opening Search exposes Close Search, and activating it collapses the field back to the Search icon. Query entry was Pro-gated, so nonempty-query behavior is not claimed as ArcZip evidence.

Stow main 33d533e, App/Browser/BrowserChrome.swift / ToolbarSearchField, currently renders Clear Search only for a nonempty query. It clears and refocuses the text field. Escape clears, releases the field and lets Browser collapse it; IME composition is explicitly protected. The user wants a visible way to close search even while empty.

Functional contract

• While search is expanded, expose an always-available, meaningfully named Close Search / 关闭搜索 action. It ends search, clears the active query/filter, collapses to the Search icon and returns keyboard focus to the file view in one action. Do not leave an invisible active filter.
• Preserve a separate Clear Search action if retained by the design: clear text while keeping search open and focused. Do not have one unlabeled × silently alternate meanings. Claude Code may choose compact placement, but Close must remain reachable in empty and nonempty states.
• Reuse the existing focus-release and query-change paths, cancel pending focus requests and prevent the surrounding capsule tap gesture from immediately reopening/refocusing search when its close control is clicked.
• Retain Command-F reopen, Escape semantics and the IME guard (Escape cancels composition before closing search). Explicit close during composition must not commit half-composed text as a query or leave a late query update after close.
• Clearing/closing stops or invalidates obsolete search result publication and restores the current folder/view mode without changing the archive or discarding staged edits. Preserve safe selection/Details consistency and no automatic opening of omitted encrypted/nested archives.
• Preserve the current trailing-toolbar order and leftward search expansion; view/delete/save controls stay stable. Respect immediate keyboard actions and reduced motion/display preferences. No mockup-fidelity requirement.

Acceptance and ownership

Codex / Grok Bot owns close/clear/focus semantics, race tests and a functional control. Claude Code owns button treatment/placement and collapse motion. Verify empty/query/no-result/indexing states, Grid/List/Columns, clicked close with focus inside/outside search, repeated Command-F/close, late search completion, keyboard activation, Pinyin/Kana composition, small windows and English/zh-Hans. A Close label with only a clear-text implementation does not satisfy this issue. Follow-up to #242/#215, not a replacement toolbar redesign.

Ownership and delivery

Codex / Grok Bot owns functional state, routing, security, cancellation, errors, tests and accessibility semantics. Claude Code owns layout, hierarchy, copy presentation, materials and motion. Functional controls may be implemented before visual review. No collaborator session or visual approval is claimed; no unknown GitHub account is assigned. Preserve basic keyboard/focus access, meaningful names, Reduce Motion/Transparency and Increase Contrast; dedicated VoiceOver acceptance remains deferred under #93. Every new user-facing string needs zh-Hans. Run relevant tests, localization and generated-plist checks for implementation; coordinate installed/registered signed artifacts with the existing release owner (#32/#38).

Dependencies and integration

Independent small change, preserving #242 layout and #215 keyboard/search semantics. Claude Code visual review is linked through #104.