fix(design): badge text clears AA — the ladder was painting a hue on a tint of itself (#3132)

Every status and priority badge used its raw hue as TEXT on a 12% tint of
that same hue. Measured on the dark palette, all six pairs failed the kit's
own AA floor: todo 1.60:1, in-progress 1.97:1, done 2.06:1, low 2.02:1,
high 2.92:1, medium 2.97:1, against 4.5. Four also failed in light mode.

The cause is structural, not a bad colour pick. A 12% tint sits near the
surface it composites over, so the hue as text on it has almost nowhere to
go. Strengthening the tint was measured and REJECTED: on a dark palette a
heavier tint moves the chip toward the light text and makes it worse. 12%
was already optimal.

So each pair gains a `-fg` sibling: the hue mixed toward --fs-text-primary
until it clears 4.5:1 worst-case over surface-raised AND surface-hover in
BOTH modes. Mixing toward that token rather than a literal is what makes one
declaration cover both — it inverts by mode, so the text follows.

Recorded in the DESIGN SYSTEM, not hand-written into theme.css: seven tokens
on design system 2, each carrying its measurement and its reasoning, then the
sheet regenerated. theme.css says not to hand-edit the --fs-* block and it is
right — a hand-edit would be silently reverted by the next regeneration.

The ladder keeps its shape. High priority still holds 52% saturation and
medium 31% — the rungs that need to shout still shout. Low, todo and done
wash toward neutral, which is what their own rationales ask for: status-todo
is derived from the border colour precisely so not-yet-started recedes.
Receding and illegible are different things and the old value was the second.

--fs-status-cancelled-fg was found by measuring, not by reasoning. Cancelled
derives from --fs-text-tertiary, which looks like the obviously-correct
"quiet" choice and is a HINT colour tuned for plain surfaces — 2.63:1 on a
badge tint in light mode.

StatusBadge additionally dropped a `color-mix(..., #000 15%)` that darkened
the hue: a light-mode instinct that made these worse on a near-black surface,
and a literal besides.

THE GUARD IS THE POINT. check_design_tokens.py now FAILS on any rule that
paints text with a token on a tint of that same token, and names the -fg
sibling as the fix. Verified by reintroducing the defect: exit 1 with it,
exit 0 without. Unlike a raw literal there is nothing to weigh up, so it
gates rather than reports.

Two `border-top-color` uses keep the raw hue, correctly — a border is a
non-text graphic and needs 3:1, which is what the hue is for.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

frontend/src/components/PriorityBadge.vue

@@ -34,14 +34,14 @@ const labels: Record<TaskPriority, string> = {
 }
 .priority-low {
   background: var(--fs-priority-low-bg);
-  color: var(--fs-priority-low);
+  color: var(--fs-priority-low-fg);
 }
 .priority-medium {
   background: var(--fs-priority-medium-bg);
-  color: var(--fs-priority-medium);
+  color: var(--fs-priority-medium-fg);
 }
 .priority-high {
   background: var(--fs-priority-high-bg);
-  color: var(--fs-priority-high);
+  color: var(--fs-priority-high-fg);
 }
 </style>

frontend/src/components/ProjectDesignTab.vue

@@ -153,7 +153,7 @@ watch(() => [props.projectId, props.designSystemId], run);
 }
 
 .pdt-clean {
-  color: var(--fs-status-done);
+  color: var(--fs-status-done-fg);
 }
 
 .pdt-summary {
@@ -206,12 +206,12 @@ watch(() => [props.projectId, props.designSystemId], run);
 
 .pdt-tag.unknown {
   background: var(--fs-priority-high-bg);
-  color: var(--fs-priority-high);
+  color: var(--fs-priority-high-fg);
 }
 
 .pdt-tag.local {
   background: var(--fs-priority-medium-bg);
-  color: var(--fs-priority-medium);
+  color: var(--fs-priority-medium-fg);
 }
 
 .pdt-tag.superseded {

frontend/src/components/StatusBadge.vue

@@ -37,21 +37,25 @@ const labels: Record<TaskStatus, string> = {
   text-transform: uppercase;
   letter-spacing: 0.025em;
 }
+/* Text comes from the -fg tokens, which are the hue mixed toward
+   --fs-text-primary until they clear AA. The old spelling darkened the hue
+   with `#000 15%` — a light-mode instinct that made these WORSE on the dark
+   palette, where the surface is already near-black, and a literal besides. */
 .status-todo {
-  background: color-mix(in srgb, var(--fs-status-todo-bg) 78%, var(--fs-status-todo) 22%);
-  color: color-mix(in srgb, var(--fs-status-todo) 85%, #000 15%);
+  background: var(--fs-status-todo-bg);
+  color: var(--fs-status-todo-fg);
 }
 .status-in_progress {
-  background: color-mix(in srgb, var(--fs-status-in-progress-bg) 78%, var(--fs-status-in-progress) 22%);
-  color: color-mix(in srgb, var(--fs-status-in-progress) 85%, #000 15%);
+  background: var(--fs-status-in-progress-bg);
+  color: var(--fs-status-in-progress-fg);
 }
 .status-done {
-  background: color-mix(in srgb, var(--fs-status-done-bg) 78%, var(--fs-status-done) 22%);
-  color: color-mix(in srgb, var(--fs-status-done) 85%, #000 15%);
+  background: var(--fs-status-done-bg);
+  color: var(--fs-status-done-fg);
 }
 .status-cancelled {
-  background: color-mix(in srgb, var(--fs-surface-raised) 78%, var(--fs-text-tertiary) 22%);
-  color: var(--fs-text-tertiary);
+  background: var(--fs-status-todo-bg);
+  color: var(--fs-status-cancelled-fg);
 }
 .clickable {
   cursor: pointer;

frontend/src/components/SystemsSection.vue

@@ -554,8 +554,8 @@ async function confirmDelete() {
 /* The two bases must never look alike — one is mechanical, the other is the
    reviewer's judgment, and that difference is the whole decision. */
 .area-basis { font-size: 0.68rem; border-radius: var(--fs-radius-sm); padding: 0.05rem 0.4rem; }
-.area-basis--exact { background: var(--fs-status-done-bg); color: var(--fs-status-done); }
-.area-basis--overlap { background: var(--fs-priority-medium-bg); color: var(--fs-priority-medium); }
+.area-basis--exact { background: var(--fs-status-done-bg); color: var(--fs-status-done-fg); }
+.area-basis--overlap { background: var(--fs-priority-medium-bg); color: var(--fs-priority-medium-fg); }
 
 .area-offer {
   display: flex;