feat(integrations): add review fetching and Linux keyring support

Add a cross-provider Review Center and improve credential handling.
Backend integrations fetch and normalize PRs from GitHub, GitLab,
Gitea, and Azure DevOps with improved timeouts and parsing. Credentials
now use a global lock and support secret-tool on Linux to avoid races.

- Normalize review data across providers (GitHub/GitLab/Gitea/Azure)
- Serialize credential access with OnceLock and use secret-tool on Linux
- Add frontend ReviewCenter component and related UI updates

src/lib/git.ts

@@ -17,6 +17,8 @@ import type {
   GitIgnoreKind,
   GitIntegrationProvider,
   GitIntegrationRepository,
+  IntegrationReviewRequest,
+  IntegrationReviewAction,
   GitLfsStatus,
   GitRepositoryFile,
   GitRemote,
@@ -59,6 +61,26 @@ export function listIntegrationRepositories(provider: GitIntegrationProvider, ba
   return invoke<GitIntegrationRepository[]>("list_integration_repositories", { provider, baseUrl, accountId: accountId ?? null });
 }
 
+export function listIntegrationReviewRequests(provider: GitIntegrationProvider, baseUrl: string, username: string, token: string, state: "open" | "merged" | "closed"): Promise<IntegrationReviewRequest[]> {
+  return invoke<IntegrationReviewRequest[]>("list_integration_review_requests", { provider, baseUrl, username, token, state });
+}
+
+export function runIntegrationReviewAction(provider: GitIntegrationProvider, baseUrl: string, username: string, token: string, request: IntegrationReviewRequest, action: IntegrationReviewAction): Promise<void> {
+  return invoke<void>("run_integration_review_action", { provider, baseUrl, username, token, repositoryId: request.repositoryId, repositoryName: request.repositoryName, number: request.number, action });
+}
+
+export function getIntegrationReviewDetails(provider: GitIntegrationProvider, baseUrl: string, username: string, token: string, request: IntegrationReviewRequest): Promise<IntegrationReviewRequest> {
+  return invoke<IntegrationReviewRequest>("get_integration_review_details", { provider, baseUrl, username, token, request });
+}
+
+export function addIntegrationReviewComment(provider: GitIntegrationProvider, baseUrl: string, username: string, token: string, request: IntegrationReviewRequest, body: string): Promise<void> {
+  return invoke<void>("add_integration_review_comment", { provider, baseUrl, username, token, request, body });
+}
+
+export function openInBrowser(url: string): Promise<void> {
+  return invoke<void>("open_in_browser", { url });
+}
+
 export function launchExternalTool(path: string, command: ExternalToolCommand, file?: string): Promise<void> {
   return invoke<void>("launch_external_tool", { path, file: file ?? null, command });
 }