[rpgmem]

Closes #2054. Stacked on #2053 (the browser name): its commit shows here until that one merges.

Problem

The "Test my device" mode (#2047) checked what a form needs, but not what support is asked about most:

• the device limit;
• odd colours;
• a wrong clock;
• a private window;
• the ALTCHA captcha's requirements;
• data saver.

A failing row did not say what to do, and a hanging check left its row without an answer.

Change

New rows, all in assets/js/ffc-device-check.js; each row is drawn by Frontend\DeviceCheck with its icon:

Row	What it shows
Local storage	Allowed / blocked (a probe key written and removed at once)
Captcha	Supported / missing Web Crypto or Web Workers
Device ID	Short code (8 hex), signals read of the site's total, stable or "changes on each read: canvas, audio"
Device clock	Correct / ahead / behind, against the Date header of a HEAD request for the page itself (no endpoint; a skew over 60 s warns)
Time zone and language	America/Sao_Paulo · UTC-3 · pt-BR
Screen	Window, screen, zoom
Connection	Online · 4G / data saver on / offline (Network Information API where the browser has it)
Theme	Dark (site: follows the system; system: dark)

Device ID

• ffc-device-signals.js exposes FFCDeviceSignals.collect(): the same signals the forms send, in a read-only mode that never creates the persistent ffc_device_id.
• The device test reads them twice. Where the device limit is off, the row says so; where the collector cannot run (no HTTPS, library blocked), it says that instead.
• DeviceCheck::enqueue_assets() now runs after the collector and declares it as a dependency when it is on the page.

How to fix it

• A row in warn or fail gets an icon-only family button (ffc-icon-info, aria-expanded, aria-controls) that reveals the fix under the result.
• There is one fix per check. The blocked-location fix depends on the platform (iOS, Android, desktop).

Countdown

• Device ID, clock, location permission and precision show "… (20 s)" while they run.
• At zero the row says "No answer after 20 s: reload the page to test again."
• 20 s covers every check's own limit: the precision read gives up at 15 s, the denied confirmation at 11 s.

Docs and catalogues

• Documentation (Certificates & Forms topic), pt_BR catalogue, CHANGELOG (Added).

Tests

• New device-check-id-theme.test.js (22 tests):
  • device ID: off, unavailable, stable with a repeatable code, changing signals named, failed read;
  • theme across settings × system preference;
  • storage allowed / blocked, with no probe left behind;
  • captcha supported / missing;
  • clock correct / ahead / behind, the exact HEAD request, unknown;
  • locale and screen;
  • connection: type, data saver, offline;
  • the information button (aria, toggle, nothing on passing rows);
  • the countdown and its timeout, and that it stops on an answer;
  • the read-only collector never creating ffc_device_id.
• DeviceCheckTest: 14 rows; every string the script reads (help keys included) is in strings(); the collector dependency.
• FrontendTest: wp_script_is stubbed.
• Run locally:
  • the full Vitest suite (2,557 tests);
  • the PHP translation, comment-language, documentation, CSS, icon, button, wiring and asset guards (238 tests);
  • PHPStan, PHPCS, ESLint, Stylelint.

Risk

• Display only, on the device test page. One HEAD request to the page itself for the clock.
• ffc-device-signals.js gains an exported read-only collector; the forms' path is unchanged.

Checklist

• Base is develop; no version bump
• CHANGELOG.md: one bullet under [Unreleased] → Added, citing Device test: device ID, theme and more diagnostics, with how to fix what fails #2054
• Documentation topic updated
• Strings in the .pot and .po, catalogues recompiled
• Minified assets rebuilt

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