web-player: final sweep and guardrails

Add scripts/check-tokens.mjs (npm run lint:tokens, wired into lint) as
a guardrail: fails if src/**/*.svelte reintroduces arbitrary values
outside the B.4 allowlist, factory rounded-*, h-N w-N pairs (should
be size-N), quarter-step fractional spacing, or literal hex/rgba()
colors.

Cleans up the repo until the script reports 0 violations: ~40 h-N w-N
pairs -> size-N (mostly icons, via a one-off script), ~26 quarter-step
fractional spacings rounded to the nearest integer (delta <=1px, e.g.
py-2.75->py-3, gap-1.75->gap-2), stray factory radii (rounded-sm/lg,
bare rounded) migrated to the matching tokens, and two
tracking-[-0.02em] that matched the existing tracking-display token
exactly but had never been migrated. Removes the
stroke-thin/regular/bold recipes (added earlier, zero consumers) —
decision made, not blocking: strokeWidth={n} (13 values, across
almost every component) isn't migrated to CSS because there's no way
to verify without Docker that lucide-svelte honors stroke-width by
class instead of the prop, and a regression there would be silent
across the whole app; the script documents this gap explicitly
instead of pretending full coverage.

Orphan detector: 0 components with no importers. Removes
docs/design-system-refactor-plan.md (earlier plan, superseded by
frontend-refactor-plan.md). web-player/CLAUDE.md gains a "Styles"
section with the B.4 allowlist and the base components to reuse.
Recalculates the baseline table (A.4) and logs it: 61->47 components,
44->11 arbitrary values (the remaining 11 on the allowlist), 13->8
distinct radii, 0 lint:tokens violations.

Verified with npm run check (0 errors), npm run lint:tokens (0
violations) and npm run build. Smoke-tested /login with no console
errors attributable to this change.

web-player/src/lib/components/player/TransportControls.svelte

@@ -12,7 +12,7 @@
 
 	const sideClass = $derived(
 		compact
-			? 'grid h-10 w-10 place-items-center text-fg opacity-70 transition active:scale-90'
+			? 'grid size-10 place-items-center text-fg opacity-70 transition active:scale-90'
 			: 'flex text-fg-2 transition-colors hover:text-fg active:scale-90'
 	);
 </script>
@@ -26,7 +26,7 @@
 			aria-label="Aleatorio"
 			class="transition-colors hover:text-fg {player.shuffle ? 'text-accent' : 'text-fg-3'}"
 		>
-			<Shuffle class="h-3.75 w-3.75" strokeWidth={1.8} />
+			<Shuffle class="size-4" strokeWidth={1.8} />
 		</button>
 	{/if}
 
@@ -58,7 +58,7 @@
 			aria-label="Repetir"
 			class="transition-colors hover:text-fg {player.repeat ? 'text-accent' : 'text-fg-3'}"
 		>
-			<Repeat class="h-3.75 w-3.75" strokeWidth={1.8} />
+			<Repeat class="size-4" strokeWidth={1.8} />
 		</button>
 	{/if}
 </div>