fix(usage): render OpenRouter PAYG credit pool with real denominator (#12468)

* fix(usage) handle OpenRouter PAYG credit percentage

OpenRouter PAYG accounts without a per-key limit previously rendered
the credits row as 'total: 0, remainingPercentage: 100, unlimited: true',
treating /credits balance as unlimited even when a real credit pool was
present. Route the credit pool through the credits renderer with the
real denominator: total = totalCredits when positive, used = total -
creditBalance, remaining = creditBalance, remainingPercentage =
round(balance / total * 100), isCredits: true, unlimited: false. Per-key
limit still wins. A non-positive pool surfaces the row but never invents
a 100% bar.

Tests cover: explicit key limit, PAYG account credits without key limit,
key limit taking priority over account credits, and a balance without a
positive denominator.

* fix(usage) render OpenRouter PAYG quota as a metered percentage bar

The frontend parser was routing every OpenRouter 'credits' quota through
buildCreditsQuota(), which sets isCredits: true. QuotaCardExpanded
short-circuits on that flag and shows only the USD balance as a bare
number, so a real PAYG payload (used: 7.33, total: 10, remaining: 2.67,
remainingPercentage: 27) was rendered as '$2.67' instead of the '27% left
/ 7.33 / 10' bar the backend already computed.

Drop isCredits: true for any payload whose total is a positive finite
number - the row then goes through the normal normalizeQuotaEntry() path
with currency preserved as an extra. The balance-only fallback (total 0
or non-finite denominator, used by legacy /credits responses) still uses
buildCreditsQuota() so the row stays renderable, and never invents a
100% percentage.

The frontend test now asserts:
- PAYG positive denominator -> total: 10, remainingPercentage: 27,
  currency: 'USD', isCredits !== true.
- Balance-only payload -> isCredits === true, creditCount === 2.67,
  total: 0, no fabricated 100%.
- NaN denominator -> balance-only fallback.
- Non-credits keys -> unchanged normalizeQuotaEntry() path.
- Mixed payload -> normal quota row + PAYG row, both kept.

* docs(changelog): add OpenRouter PAYG fix fragment

* docs(changelog): remove self credit

src/app/(dashboard)/dashboard/usage/components/ProviderLimits/quotaParsing.ts

@@ -331,13 +331,26 @@ function parseAgentrouter(data: any) {
 // USD. Free-tier request windows keep the generic percentage treatment.
 function parseOpenrouterQuota(quotaKey: string, quota: any) {
   if (quotaKey !== "credits") return normalizeQuotaEntry(quotaKey, quota);
+  // OpenRouter backend (PRs #12256 + #12468) reports a positive-denominator
+  // PAYG payload (used, total, remaining, remainingPercentage) and a
+  // balance-only payload under legacy keys. The credits renderer in
+  // QuotaCardExpanded short-circuits when `isCredits: true` and only shows
+  // the remaining balance as USD - so a positive-denominator PAYG row
+  // must NOT take that branch. Positive denominators go through the regular
+  // normalizeQuotaEntry() path (which keeps currency as an extra); only a
+  // missing/non-positive denominator falls back to buildCreditsQuota() so
+  // the balance row stays renderable without inventing a 100% percentage.
+  const total = Number(quota?.total ?? 0);
+  if (Number.isFinite(total) && total > 0) {
+    return normalizeQuotaEntry(quotaKey, quota, {
+      currency: quota?.currency ?? "USD",
+    });
+  }
   const remaining = Math.max(0, Number(quota?.remaining ?? 0));
-  const currency = quota?.currency || "USD";
-  const remainingPercentage =
-    safePercentage(quota?.remainingPercentage) ?? (remaining > 0 ? 100 : 0);
+  const currency = quota?.currency ?? "USD";
+  const remainingPercentage = safePercentage(quota?.remainingPercentage) ?? 0;
   return buildCreditsQuota("credits", remaining, remainingPercentage, { currency });
 }
-
 function parseOpenrouter(data: any) {
   return quotaEntries(data).map(([quotaKey, quota]) => parseOpenrouterQuota(quotaKey, quota));
 }