feat: add useSpeedTestEndpoints hook to collect all endpoint candidates for speed test modal

- Create useSpeedTestEndpoints hook that collects endpoints from:
  1. Current baseUrl/codexBaseUrl
  2. Initial data URL (edit mode)
  3. Preset's endpointCandidates array
- Pass speedTestEndpoints to ClaudeFormFields and CodexFormFields
- Update EndpointSpeedTest to use collected endpoints instead of just current URL
- Fix PackyCode preset endpoints not appearing in speed test modal

src/components/providers/forms/hooks/index.ts

@@ -9,3 +9,4 @@ export { useKimiModelSelector } from "./useKimiModelSelector";
 export { useTemplateValues } from "./useTemplateValues";
 export { useCommonConfigSnippet } from "./useCommonConfigSnippet";
 export { useCodexCommonConfig } from "./useCodexCommonConfig";
+export { useSpeedTestEndpoints } from "./useSpeedTestEndpoints";