feat(server,app): redesign git/GitHub refresh architecture with server authority

Centralizes refresh orchestration in WorkspaceGitService and GitHubService:
server coalesces, deduplicates, and throttles git/GitHub reads; clients peek
snapshots (cold reads fall through to a one-shot fetch) and never drive
refreshes. Introduces a two-TTL model (consumer vs internal), force-emit
bypass so fingerprint-matched refreshes still propagate, notifyGitMutation
wiring at ~13 action handlers, adaptive GitHub polling based on check state,
and checkout_status_update / prStatus push-to-cache wire messages. Fixes the
stale diff-stat bug and the inverted base-branch diff direction, and flips
next-action affordances promptly after commit / PR merge.

packages/app/src/screens/workspace/workspace-screen.tsx

@@ -741,9 +741,6 @@ function WorkspaceScreenContent({ serverId, workspaceId }: WorkspaceScreenProps)
     }
 
     const unsubscribeChanged = client.on("terminals_changed", (message) => {
-      if (message.type !== "terminals_changed") {
-        return;
-      }
       if (message.payload.cwd !== workspaceDirectory) {
         return;
       }
@@ -776,7 +773,10 @@ function WorkspaceScreenContent({ serverId, workspaceId }: WorkspaceScreenProps)
       }
       return (await client.getCheckoutStatus(workspaceDirectory)) as CheckoutStatusPayload;
     },
-    staleTime: 15_000,
+    staleTime: Infinity,
+    refetchOnMount: false,
+    refetchOnReconnect: false,
+    refetchOnWindowFocus: false,
   });
   const isCheckoutStatusLoading =
     isCheckoutQueryEnabled && checkoutQuery.data === undefined && !checkoutQuery.isError;