fix: reclassify ClaudeAPI as aggregator to re-enable model test

ClaudeAPI supports the health/stream check, but the third_party
category triggers the isClaudeThirdParty gate in ProviderCard that
disables the model test button for third-party Claude providers.
Recategorizing as aggregator restores the test action; the partner
star is unaffected since it is driven by isPartner, not category.

Applied to both the Claude Code and Claude Desktop presets.

src/config/claudeDesktopProviderPresets.ts

@@ -579,7 +579,7 @@ export const claudeDesktopProviderPresets: ClaudeDesktopProviderPreset[] = [
     name: "ClaudeAPI",
     websiteUrl: "https://claudeapi.com",
     apiKeyUrl: "https://console.claudeapi.com/register?aff=pCLD",
-    category: "third_party",
+    category: "aggregator",
     baseUrl: "https://gw.claudeapi.com",
     mode: "direct",
     apiFormat: "anthropic",

src/config/claudeProviderPresets.ts

@@ -614,7 +614,7 @@ export const providerPresets: ProviderPreset[] = [
         ANTHROPIC_AUTH_TOKEN: "",
       },
     },
-    category: "third_party",
+    category: "aggregator",
     isPartner: true,
     partnerPromotionKey: "claudeapi",
     icon: "claudeapi",