feat(quota): add usage tracking for Groq

First slice of #3701: quota tracking for Groq via x-ratelimit-* response
headers on the models endpoint (no dedicated quota endpoint exists, and
reading usage costs zero tokens).

- usage/groq.js: parse request+token limit/remaining headers; Go-style
  duration reset headers ("2m59.56s") resolve to future timestamps;
  missing key/401/403 -> message, 2xx without headers -> soft
  "not tracked yet" with quotas:{}
- registry/groq.js: transport.usage.url (reuses validateUrl) +
  features {usage, usageApikey}
- services/usage.js: groq entry in USAGE_HANDLERS
- ProviderLimits/utils.js: parseQuotaData case (absolute used/total,
  codex/kiro style)
- tests: groq-usage.test.js (registry flags, header parsing, soft
  not-tracked path, missing key/401, parseQuotaData)

src/app/(dashboard)/dashboard/usage/components/ProviderLimits/utils.js

@@ -542,6 +542,21 @@ export function parseQuotaData(provider, data) {
         }
         break;
 
+      case "groq":
+        // Requests/Tokens rate-limit windows from response headers — absolute
+        // used/total (calculatePercentage derives the bar), like Codex/Kiro.
+        if (data.quotas) {
+          Object.entries(data.quotas).forEach(([name, quota]) => {
+            normalizedQuotas.push({
+              name,
+              used: quota.used || 0,
+              total: quota.total || 0,
+              resetAt: quota.resetAt || null,
+            });
+          });
+        }
+        break;
+
       case "ollama":
         // Session (5h) / Weekly (7d) usage % from ollama.com/api/usage.
         // remainingPercentage only — no absolute remaining (UI treats remaining as %).