fix(settings): red Clear Cache button, confirm when it's done

role: .destructive alone wasn't rendering red on its own — explicit
.buttonStyle(.borderedProminent).tint(.red), matching how other
destructive actions in the app (DocumentShareSheet's Revoke) had to
be styled explicitly too. Also shows a transient "Cleared" checkmark
for 2s after finishing, same timed-reset pattern as the share sheet's
copy-link feedback, since the storage count updating alone was easy
to miss.

Outpost/Features/Account/SettingsView.swift

@@ -21,6 +21,7 @@ struct SettingsView: View {
     @State private var pendingOperations: [PendingOperationSummary] = []
     @State private var isSyncing = false
     @State private var isClearingCache = false
+    @State private var didClearCache = false
     @State private var lastFullSyncSummary: FullSyncSummary?
     @State private var lastFlushSummary: SyncFlushSummary?
 
@@ -288,9 +289,14 @@ struct SettingsView: View {
                 .frame(maxWidth: 480)
 
             VStack(alignment: .leading, spacing: 6) {
-                HStack {
+                HStack(spacing: 10) {
                     Text("Clear All Cache")
                     Spacer()
+                    if didClearCache {
+                        Label("Cleared", systemImage: "checkmark")
+                            .font(.caption)
+                            .foregroundStyle(.secondary)
+                    }
                     Button(role: .destructive) {
                         Task { await clearCache() }
                     } label: {
@@ -300,6 +306,8 @@ struct SettingsView: View {
                             Text("Clear")
                         }
                     }
+                    .buttonStyle(.borderedProminent)
+                    .tint(.red)
                 }
                 Text("Deletes every cached collection and document, including anything Full Local Sync built, and anything still waiting to sync. Doesn't touch the server. This is the only place that can — it works even while offline, which is exactly why it's behind this toggle.")
                     .font(.caption2)
@@ -410,6 +418,11 @@ struct SettingsView: View {
         defer { isClearingCache = false }
         await cachingClient.clearCache()
         await refreshSyncState()
+        didClearCache = true
+        Task {
+            try? await Task.sleep(for: .seconds(2))
+            didClearCache = false
+        }
     }
 }
 #endif