Author filter chips composable with repo/unread filters; 'mine' pinned first

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DgBEW6qAwgn2fcQbA2f4ZQ

shared/types.ts

@@ -88,6 +88,8 @@ export interface FailureReport extends FailureReportSummary {
 }
 
 export interface StatePayload {
+  /** The configured GitHub login this dashboard belongs to. */
+  user: string;
   prs: PrSnapshot[];
   lastSyncAt: string | null;
   lastSyncError: string | null;