perf: reduce redundant fetches and improve list render efficiency

- Remove no-op per-row task from RepositoryListView; loadMoreIfNeeded
  is a stub for repos so each row was allocating a Task that did nothing
- Fix BuildListView auto-refresh stopping permanently after navigating
  away; startAutoRefresh now runs unconditionally on task so it restarts
  on every reappear, not just first load
- Add lastRefreshed tracking to HomeViewModel with a needsRefresh(after:)
  helper; HomeView and WorkView scene-activation handlers now skip
  loadDashboard() if the data is less than 60 seconds old
- Add 120-second TTL to repository build status refresh; statuses are
  no longer re-fetched on every tab appear, only when stale or when the
  user explicitly pulls to refresh (forceRefresh: true)

Implements: https://todo.sr.ht/~ccleberg/hutch/56

1 files changed, 8 insertions, 0 deletions

diff --git a/Hutch/Views/Home/HomeViewModel.swift b/Hutch/Views/Home/HomeViewModel.swift
index f0c14dd..ec54759 100644
--- a/Hutch/Views/Home/HomeViewModel.swift
+++ b/Hutch/Views/Home/HomeViewModel.swift
@@ -188,6 +188,7 @@ final class HomeViewModel {
     private(set) var projectsError: String?
     private(set) var assignedTicketsError: String?
     private(set) var recentBuildsError: String?
+    private(set) var lastRefreshed: Date?
 
     private let currentUser: User
     private let client: SRHTClient
@@ -405,10 +406,17 @@ final class HomeViewModel {
             systemStatusErrorMessage = error.userFacingMessage
         }
         isLoadingSystemStatus = false
+        lastRefreshed = Date()
         persistNeedsAttentionSnapshot()
         persistSystemStatusWidgetSnapshot()
     }
 
+    /// Returns true if sufficient time has elapsed since the last dashboard refresh.
+    func needsRefresh(after interval: TimeInterval = 60) -> Bool {
+        guard let lastRefreshed else { return true }
+        return Date().timeIntervalSince(lastRefreshed) > interval
+    }
+
     var hasDashboardContent: Bool {
         !pinnedProjects.isEmpty || !assignedTickets.isEmpty || !recentBuilds.isEmpty || !unreadInboxThreads.isEmpty || systemStatusSnapshot != nil
     }