Diff hunks + thread context on review comments; preview env links; hide matrix placeholder

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

server/github/queries.ts

@@ -16,6 +16,7 @@ export const LIST_QUERY = /* GraphQL */ `
           headRefName
           headRefOid
           repository { nameWithOwner }
+          labels(first: 20) { nodes { name } }
           commits(last: 1) { nodes { commit { statusCheckRollup { state } } } }
           reviewThreads(first: 50) { totalCount nodes { isResolved } }
           comments(first: 1) { totalCount }
@@ -38,6 +39,7 @@ export interface ListPr {
   headRefName: string;
   headRefOid: string;
   repository: { nameWithOwner: string };
+  labels: { nodes: { name: string }[] };
   commits: { nodes: { commit: { statusCheckRollup: { state: string } | null } }[] };
   reviewThreads: { totalCount: number; nodes: { isResolved: boolean }[] };
   comments: { totalCount: number };
@@ -90,7 +92,7 @@ export const DETAIL_QUERY = /* GraphQL */ `
             isResolved
             path
             comments(first: 30) {
-              nodes { id author { login } bodyText createdAt updatedAt url }
+              nodes { id author { login } bodyText createdAt updatedAt url diffHunk }
             }
           }
         }
@@ -110,6 +112,8 @@ export interface DetailComment {
   createdAt: string;
   updatedAt: string;
   url: string;
+  /** Present only on review-thread comments. */
+  diffHunk?: string;
 }
 
 export interface DetailPr {