fix: avoid sync github credential reads in provider manager (#428)

* fix: avoid sync github credential reads in provider manager

* test: stabilize provider manager async credential test

* fix: avoid first-frame github provider false negative

---------

Co-authored-by: KRATOS <84986124+gnanam1990@users.noreply.github.com>

src/utils/githubModelsCredentials.hydrate.test.ts

@@ -41,7 +41,7 @@ describe('hydrateGithubModelsTokenFromSecureStorage', () => {
     }))
 
     const { hydrateGithubModelsTokenFromSecureStorage } = await import(
-      './githubModelsCredentials.js'
+      './githubModelsCredentials.js?hydrate=sets-token'
     )
     hydrateGithubModelsTokenFromSecureStorage()
     expect(process.env.GITHUB_TOKEN).toBe('stored-secret')
@@ -62,7 +62,7 @@ describe('hydrateGithubModelsTokenFromSecureStorage', () => {
     }))
 
     const { hydrateGithubModelsTokenFromSecureStorage } = await import(
-      './githubModelsCredentials.js'
+      './githubModelsCredentials.js?hydrate=preserve-existing'
     )
     hydrateGithubModelsTokenFromSecureStorage()
     expect(process.env.GITHUB_TOKEN).toBe('already')