fix(web): use the terracotta accent instead of green for done checkmarks

text-primary instead of text-success — keeps the "done" state on-brand
with the rest of the UI (buttons, focus rings) rather than introducing
a separate green that only really worked well on the dark theme.

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

web/src/lib/components/ToolCallCard.svelte

@@ -14,7 +14,7 @@
   const statusColor = $derived.by(() => {
     if (status === 'running') return 'text-primary'
     if (status === 'error') return 'text-destructive'
-    return 'text-success'
+    return 'text-primary'
   })
 
   const argsSummary = $derived.by(() => {