T9.3 - S6: one icon system - monochrome text glyphs, one meaning each

The set mixed colour emoji with dingbats, and the same glyph read as two
things partly BECAUSE emoji render as per-platform artwork. The system chosen:
monochrome text-presentation glyphs - the suite is classic-script vanilla HTML
with no bundler, so an SVG sprite or icon font is a new asset pipeline, while
text glyphs render through the same font stack as the words beside them. The
enforceable form of "renders identically on Windows, macOS and a tablet":
no emoji-range codepoint and no U+FE0F selector anywhere in UI source,
swept by the probe on every run.

Converted: green-check/red-cross emoji in the admin and users consoles to
checkmark/cross, no-entry to circled-slash (blocked/on hold), the lock to the
pencil already meaning "edit with a logged reason" on sign-offs, the star to
the diamond, the folder to the reference marker, the side nav's lightning to
the gear, and the WATCH glyph (U+231A - emoji-presentation BY DEFAULT per
Unicode) to a text-presentation clock face. Dropped where the label already
carried the meaning: lightning on Save & view, the camera on Add photo, the
page/frame pictograms on file rows (the filename is the label). Stale help
copy fixed while its emoji left: it still described the pre-T9.4 "Load
sample" and the pre-T7.10 "Usage Logs" locations.

The meaning-to-icon mapping is in docs/reference/tokens.md - one meaning per
glyph, one glyph per meaning, both directions asserted from the document
itself; the probe also sweeps every page for glyphs not in the approved set,
so an unmapped icon cannot creep in.

Verification (each probe run alone): NEW tests/icon_check.py 5/5.
Regressions: frame_check 38/38, files_check 36/36, a11y_check 22/22,
cards_check 44/44.

Items: S6

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

html/wp-sidenav.js

@@ -43,7 +43,7 @@
     { section: 'People' },
     { href: 'users.html', match: /(^|\/)users\.html$/, icon: '☺', label: 'User Directory',
       sub: 'Who\'s on the project' },
-    { href: 'admin.html', match: /(^|\/)admin\.html$/, icon: '⚡', label: 'Admin Console',
+    { href: 'admin.html', match: /(^|\/)admin\.html$/, icon: '⚙', label: 'Admin Console',
       sub: 'Settings & diagnostics',
       show: function () { return typeof window.wpIsAdmin === 'function' && window.wpIsAdmin(); } },
     // Account actions, inherited from the flat user menu that used to sit in the app
@@ -51,7 +51,7 @@
     // drawer already had; these two were its only unique contents, so they moved here
     // rather than being lost with it. `action` items render as buttons, not links.
     { section: 'Account' },
-    { action: 'wpPreferences', icon: '⌚', label: 'Language & time',
+    { action: 'wpPreferences', icon: '◷', label: 'Language & time',
       sub: 'Dates, numbers and time zone' },
     { action: 'wpChangePassword', icon: '⚿', label: 'Password', sub: 'Change your password' },
   ];