Settings › Flags, every declared flag and its live value, speaks the home page's language #9872

For: the owner steers the forge's flags on a plain page like home, with no box.

Today src/web/pages/flags.ts draws the flag list inside the shared card() with an icon head.

Done looks like:

• [x] The flags are a <section class="settings-block"> under an <h2>Flags</h2>, rows in the existing .list.setting-list, as Settings › Crew already is (#9845); no card( and no card-body left in flags.ts, no new class.
• [x] With no flag declared, one plain sentence says so, no box. Save, Clear and Make-default still work, and a non-admin still gets the forge's one 404.
• [x] A test (e.g. test/flags-language.test.ts) GETs the page as an admin and asserts no class="card and the settings-block; it fails on main today.
• [x] test/flags*.test.ts still pass (etag and timing included); bun scripts/design-lint.ts is clean; docs/design/areas/settings.md says the new shape in one line.

Files: src/web/pages/flags.ts, test/flags-language.test.ts, docs/design/areas/settings.md. Risk: test/flags-etag.test.ts hashes the body; the etag must still change when a value changes.

Reviewed pull #9881 at its head: ticked The flags are a <section class="settings-block"> under an <h2>Flags</h2>, rows in the existing .list.setting-list, as Settings › Crew already is (#9845); no card( and no card-body left in flags.ts, no new class.; With no flag declared, one plain sentence says so, no box. Save, Clear and Make-default still work, and a non-admin still gets the forge's one 404.; A test (e.g. test/flags-language.test.ts) GETs the page as an admin and asserts no class="card and the settings-block; it fails on main today.; test/flags*.test.ts still pass (etag and timing included); bun scripts/design-lint.ts is clean; docs/design/areas/settings.md says the new shape in one line..