feat(quota): add Claude OAuth usage quota detection

Add Claude quota section to the Quota Management page, using the
Anthropic OAuth usage API (api.anthropic.com/api/oauth/usage) to
display utilization across all rate limit windows (5-hour, 7-day,
Opus, Sonnet, etc.) and extra usage credits.

src/pages/QuotaPage.module.scss

@@ -103,6 +103,7 @@
 }
 
 .antigravityGrid,
+.claudeGrid,
 .codexGrid,
 .geminiCliGrid {
   display: grid;
@@ -115,6 +116,7 @@
 }
 
 .antigravityControls,
+.claudeControls,
 .codexControls,
 .geminiCliControls {
   display: flex;
@@ -125,6 +127,7 @@
 }
 
 .antigravityControl,
+.claudeControl,
 .codexControl,
 .geminiCliControl {
   display: flex;
@@ -145,6 +148,12 @@
   align-items: center;
 }
 
+.claudeCard {
+  background-image: linear-gradient(180deg,
+      rgba(252, 228, 236, 0.18),
+      rgba(252, 228, 236, 0));
+}
+
 .antigravityCard {
   background-image: linear-gradient(180deg,
       rgba(224, 247, 250, 0.12),