Add GitHub integration for PRs, issues and AI PR description (#205)

* feat: integrate GitHub OAuth device flow across runtimes

Add GitHub OAuth device flow endpoints across runtimes
Introduce GitHubSettings UI panel and sidebar entry
Persist GitHub auth state in per-runtime storage

* feat: add GitHub PR status and PR description generation

Show PR status for the current branch in the Git view
Generate a pull request description from the diff between base and head
Expose prStatus, prCreate, and prMerge APIs in web and desktop clients

* feat: add GitHub PR ready for review

Add API to mark pull requests as ready for review
Show a Ready button for draft PRs and reflect status in UI
Handle token expiration and GraphQL errors when marking ready

packages/vscode/webview/api/github.ts

@@ -0,0 +1,34 @@
+import type {
+  GitHubAPI,
+  GitHubAuthStatus,
+  GitHubPullRequest,
+  GitHubPullRequestCreateInput,
+  GitHubPullRequestMergeInput,
+  GitHubPullRequestMergeResult,
+  GitHubPullRequestReadyInput,
+  GitHubPullRequestReadyResult,
+  GitHubPullRequestStatus,
+  GitHubDeviceFlowComplete,
+  GitHubDeviceFlowStart,
+  GitHubUserSummary,
+} from '@openchamber/ui/lib/api/types';
+
+import { sendBridgeMessage } from './bridge';
+
+export const createVSCodeGitHubAPI = (): GitHubAPI => ({
+  authStatus: async () => sendBridgeMessage<GitHubAuthStatus>('api:github/auth:status'),
+  authStart: async () => sendBridgeMessage<GitHubDeviceFlowStart>('api:github/auth:start'),
+  authComplete: async (deviceCode: string) =>
+    sendBridgeMessage<GitHubDeviceFlowComplete>('api:github/auth:complete', { deviceCode }),
+  authDisconnect: async () => sendBridgeMessage<{ removed: boolean }>('api:github/auth:disconnect'),
+  me: async () => sendBridgeMessage<GitHubUserSummary>('api:github/me'),
+
+  prStatus: async (directory: string, branch: string) =>
+    sendBridgeMessage<GitHubPullRequestStatus>('api:github/pr:status', { directory, branch }),
+  prCreate: async (payload: GitHubPullRequestCreateInput) =>
+    sendBridgeMessage<GitHubPullRequest>('api:github/pr:create', payload),
+  prMerge: async (payload: GitHubPullRequestMergeInput) =>
+    sendBridgeMessage<GitHubPullRequestMergeResult>('api:github/pr:merge', payload),
+  prReady: async (payload: GitHubPullRequestReadyInput) =>
+    sendBridgeMessage<GitHubPullRequestReadyResult>('api:github/pr:ready', payload),
+});