chore(ui): move to Font Awesome 7, with no v4 shims

[mastacontrola]

FOG shipped Font Awesome 4.7.0 — nine years old. This vendors 7.3.1 and migrates every call site, deliberately without v4-shims.css.

A shim layer is one you can never remove, because nothing ever tells you when its last consumer goes away. Dropping it is only safe if something checks the call sites, so this adds that check instead of the shims.

What the FA4 names actually do under FA7

I initially described all 26 as blank boxes. That was measured wrong — a ::before with content set is not proof of a glyph. Rasterising each against the shipped build and counting non-transparent pixels splits them three ways:

behaviour	count	which
render nothing	8	check-square-o, circle-o, file-excel-o, hdd-o, money, moon-o, square-o, sun-o — all the FA4 -o outline variants, whose glyphs moved to the regular family without the old names being kept
render the wrong glyph	2	windows, slack — brand codepoints while .fa selects the solid font, so they draw a tofu box
render correctly today	16	refresh, magic, warning, dashboard, globe, … — FA7 kept the old name as an alias

The tell on the tofu pair: both measured ink=1452, identical to each other. Two different icons can't have the same pixel count.

So this is worth less as a bug fix than I first claimed, and more as maintenance: two thirds of these look fine in a browser right now and break whenever FontAwesome drops the aliases. That's exactly the change nobody catches by looking — which is the argument for the test, not against the work.

What changed

68 call sites across core. 26 FA4-only names, 11 FA5-era aliases (fa-times-circle → fa-circle-xmark, fa-cogs → fa-gears), and 46 canonical names still on the bare fa prefix — .fa resolves to solid in FA7 so those rendered either way, but leaving part of the codebase on the old prefix is the inconsistency this pass exists to remove.

Payload

6 font formats (~500KB) → 3 woff2 (~254KB). Costs IE11 and pre-2014 browsers, already unusable on this Bootstrap 5 UI. The vendored CSS is byte-identical to upstream all.min.css so the next upgrade is a straight file swap; fa-v4compatibility.woff2 ships only because that CSS references it, and an unused @font-face is never fetched.

Menu icons fixed while the names were changing anyway

item	was	now	why
Storagenodes	box-archive	server	an archive box is not a storage node
Roles	key	user-shield	roles are permissions, not credentials
Audit Log	shield	clipboard-list	a shield is protection; a log is a record
iPXE Menu	bars	list-ol	fa-bars is the hamburger glyph
User Groups	address-book	people-group	collided with the LDAP plugin
Sites	location-dot	building	collided with the Location plugin
Modules	gears	sliders	collided with Client Settings

Checking these against fog-plugins found five icons serving two different menu items each. Core and plugins now use 38 distinct icons with none shared — an icon that means two things is the same navigation problem as a wrong one.

Bonus fix: toasts have had no icon since Bootstrap 5

PNotify was left on its bootstrap3 styling, which emits glyphicon classes — dropped in Bootstrap 4. Every notice has been rendering content: none at zero width ever since. Its fontawesome preset is FA4, so switching alone would have traded one blank box for another; the names are overridden at our call site in fog.common.js, not in the vendored pnotify.min.js, because editing that means the next upgrade silently reverts the fix.

Verified on the lab

All three font families load, brands woff2 serves 200, zero blank glyphs across 45 distinct icon classes, every sidebar entry renders, and both toast types now draw a 20px icon.

Tests

tests/fontawesome7-icon-names.test.php — 14 checks, 9 mutants killed: an FA4 name creeping back, a bare fa prefix, a pro-only name (absent from the free build and just as blank), the shims returning, a missing webfont, and the PNotify override being undone.

Downstream

FOG_PLUGINS_VERSION bumped to v1.6.15 in this PR, which is the matching plugin migration (FOGProject/fog-plugins#25, released). Pinned here rather than as a follow-up so no install lands between new core and FA4 plugin icons.