feat: add support for GitHub Models provider

- Introduced environment variable CLAUDE_CODE_USE_GITHUB to enable GitHub Models.
- Added checks for GITHUB_TOKEN or GH_TOKEN for authentication.
- Updated base URL handling to include GitHub Models default.
- Enhanced provider detection and error handling for GitHub Models.
- Updated relevant functions and components to accommodate the new provider.

src/utils/githubModelsCredentials.hydrate.test.ts

@@ -0,0 +1,66 @@
+/**
+ * Hydrate tests live in a separate file with no static import of
+ * githubModelsCredentials so Bun's mock.module can replace secureStorage
+ * before that module is first loaded.
+ */
+import { afterEach, describe, expect, mock, test } from 'bun:test'
+
+describe('hydrateGithubModelsTokenFromSecureStorage', () => {
+  const orig = {
+    CLAUDE_CODE_USE_GITHUB: process.env.CLAUDE_CODE_USE_GITHUB,
+    GITHUB_TOKEN: process.env.GITHUB_TOKEN,
+    GH_TOKEN: process.env.GH_TOKEN,
+    CLAUDE_CODE_SIMPLE: process.env.CLAUDE_CODE_SIMPLE,
+  }
+
+  afterEach(() => {
+    mock.restore()
+    for (const [k, v] of Object.entries(orig)) {
+      if (v === undefined) {
+        delete process.env[k as keyof typeof orig]
+      } else {
+        process.env[k as keyof typeof orig] = v
+      }
+    }
+  })
+
+  test('sets GITHUB_TOKEN from secure storage when USE_GITHUB and env token empty', async () => {
+    process.env.CLAUDE_CODE_USE_GITHUB = '1'
+    delete process.env.GITHUB_TOKEN
+    delete process.env.GH_TOKEN
+    delete process.env.CLAUDE_CODE_SIMPLE
+
+    mock.module('./secureStorage/index.js', () => ({
+      getSecureStorage: () => ({
+        read: () => ({
+          githubModels: { accessToken: 'stored-secret' },
+        }),
+      }),
+    }))
+
+    const { hydrateGithubModelsTokenFromSecureStorage } = await import(
+      './githubModelsCredentials.js'
+    )
+    hydrateGithubModelsTokenFromSecureStorage()
+    expect(process.env.GITHUB_TOKEN).toBe('stored-secret')
+  })
+
+  test('does not override existing GITHUB_TOKEN', async () => {
+    process.env.CLAUDE_CODE_USE_GITHUB = '1'
+    process.env.GITHUB_TOKEN = 'already'
+
+    mock.module('./secureStorage/index.js', () => ({
+      getSecureStorage: () => ({
+        read: () => ({
+          githubModels: { accessToken: 'stored-secret' },
+        }),
+      }),
+    }))
+
+    const { hydrateGithubModelsTokenFromSecureStorage } = await import(
+      './githubModelsCredentials.js'
+    )
+    hydrateGithubModelsTokenFromSecureStorage()
+    expect(process.env.GITHUB_TOKEN).toBe('already')
+  })
+})