refactor(tokens): extract subscription urgent + critical semantic colors

The #FFB800 (23 hits) and #FF3B5C (11 hits) raw hex literals across
Subscription / SubscriptionPurchase / TrialOfferCard / useTrafficZone
all represent the same semantic: 'expiring soon' and 'expired'.
Distinct from warning-500 (#f59e0b) and error-500 (#ef4444) — the
subscription timeline needs a sharper, hotter signal than the
system-wide warning/error roles.

Add two semantic tokens:
  --color-urgent-400:   255, 184, 0    (#FFB800)
  --color-critical-500: 255, 59, 92    (#FF3B5C)

Exposed via Tailwind as urgent.400 / critical.500. Sweep all
single-and double-quoted hex literals to rgb(var(--color-...))
form so style attrs, SVG stroke=, and ternary string values all
resolve through CSS vars (auto-respects future light-theme
variants).

Left as-is: 4 hex appearances inside gradient pair strings —
linear-gradient(135deg, #FFB800, #FF8C00) — where the partner
color (#FF8C00 / #FF6B35) isn't in the token set. Partial-replace
inside gradient strings would just add noise; full extraction of
the orange-ramp companion is out of scope for this pass.

src/styles/globals.css

@@ -180,6 +180,13 @@
     --color-error-900: 127, 29, 29;
     --color-error-950: 69, 10, 10;
 
+    /* Subscription-status semantic tokens — distinct from warning/error
+       because the urgency timeline ("expiring soon" vs "expired") needs a
+       sharper, hotter signal than the system-wide warning/error roles.
+       Extracted from inline #FFB800 / #FF3B5C in Subscription.tsx etc. */
+    --color-urgent-400: 255, 184, 0; /* #FFB800 — expiring soon */
+    --color-critical-500: 255, 59, 92; /* #FF3B5C — expired */
+
     /* Theme semantic colors (hex for direct use) */
     --color-dark-bg: #0a0f1a;
     --color-dark-surface: #0f172a;