ui(free): result filters as native WP navigation with counts and an active state #274

Part of a presentation-only UI/UX polish set for the WriteLeash Free admin screens. Shared constraints and the merge gate are at the bottom of this issue — read them before starting.

Problem

The Results screen product filters are rendered as a row of loose buttons with no visible active state:

• wordpress/writeleash/includes/free/class-free-admin.php:2641-2646: <p class="writeleash-filters"> contains <a class="button"> per choice, with <strong> used for the active choice. Six choices: All products / Conflicts / Changes needing attention / Uncertain changes / Undo conflicts / Uncertain restorations.
• wordpress/writeleash/includes/free/free-selection.css:120-125 styles them as a flex row; there is no .current/active styling, no counts, and the row wraps awkwardly at narrow widths.
• Reference screenshot: wordpress/assets/screenshot-4.png (the button row above the Products table).

Scope

• wordpress/writeleash/includes/free/class-free-admin.php (filter renderer only, ~L2639-2646)
• wordpress/writeleash/includes/free/free-selection.css (replace .writeleash-filters block)

Required direction

1. Use WordPress's standard list navigation pattern: ul.subsubsub with pipe separators and one .current item — the same pattern as Posts/Users screens (All products | Conflicts (2) | …). Active item gets .current plus aria-current="page".
2. Keep every URL, the filter query parameter and the fallback behavior exactly as today (unknown filter falls back to All). No handler changes.
3. Counts are optional and cheap only: render Label (n) where an existing repository call already provides the number for every filter in one place. Do NOT add new storage, caches or per-filter queries for this issue. If counts are not available cheaply, ship the pattern without counts and say so in the PR.
4. Keep the existing empty-state row ("No retained products on this page match this view.") unchanged.

Acceptance criteria

• Active filter is visually unambiguous (.current) and exposed via aria-current.
• Markup matches the WP subsubsub pattern; keyboard reachable; focus visible.
• Wraps gracefully at 782px and 375px (no horizontal overflow).
• URLs/query params unchanged; deep links to a filter still work.
• Screenshots (all filters, active vs inactive) in the PR.

Shared constraints (all UI-polish issues)

• Presentation only: do not change planner math, frozen decimal/display contracts, storage, handlers, nonces, form field names, routes, capabilities or job logic.
• Native WordPress UI only: .wrap, .button, .widefat, .notice, Dashicons. No React, no CSS framework, no gradients/hero/decorative art, no new icon fonts.
• All CSS stays scoped under .writeleash-admin; do not touch global wp-admin styles or other screens.
• WordPress admin palette only; meaning is never conveyed by color alone; visible focus 2px #2271b1; body-text contrast ≥ 4.5:1.
• Works at 1440 / 1024 / 782 / 375 px and at 200% zoom.
• User-facing strings stay translatable (writeleash text domain); if strings change, note it in the PR.

Merge gate (required)

Single-owner repository. The implementing agent MUST open a pull request and MUST NOT merge it: no self-merge, no auto-merge, no direct push to main, no force-push after review starts. Only @MrDarkRoot reviews and merges. PR_FAST and CI_COVERAGE must be green, and these files carry the admin + acceptance ownership gates (.github/ci/path-ownership.json).