feat(settings): grey out server-synced settings while offline

Profile's name/avatar and every Preferences toggle (except Appearance,
which is local-only) now disable + show a hint when isEffectivelyOnline
is false, instead of letting a save silently fail. Matches how Share/
Permissions/Search already behave — these are a "needs a real connection"
category, not queued through the offline write queue (infrequent writes,
not worth a second offline-sync path for).

Outpost/Features/Account/SettingsView.swift

@@ -127,6 +127,9 @@ struct SettingsView: View {
     private var profileDetail: some View {
         VStack(alignment: .leading, spacing: 24) {
             sectionHeader
+            if !isEffectivelyOnline {
+                offlineSettingsHint
+            }
             avatarRow
             Divider().frame(maxWidth: 420)
             nameRow
@@ -184,6 +187,7 @@ struct SettingsView: View {
                         ProgressView().controlSize(.small)
                     }
                 }
+                .disabled(!isEffectivelyOnline)
                 if let avatarErrorMessage {
                     Text(avatarErrorMessage)
                         .font(.caption)
@@ -212,6 +216,7 @@ struct SettingsView: View {
                     }
                 }
             }
+            .disabled(!isEffectivelyOnline)
             if let nameErrorMessage {
                 Text(nameErrorMessage)
                     .font(.caption)
@@ -248,8 +253,13 @@ struct SettingsView: View {
                 .font(.subheadline)
                 .foregroundStyle(.secondary)
 
+            if !isEffectivelyOnline {
+                offlineSettingsHint
+            }
+
             preferencesSubsection("Display") {
                 languageRow
+                    .disabled(!isEffectivelyOnline)
                 Divider()
                 appearanceRow
                 Divider()
@@ -259,6 +269,7 @@ struct SettingsView: View {
                     isOn: session.userPreferences?.useCursorPointer ?? false,
                     onChange: { newValue in Task { await savePreference { $0.useCursorPointer = newValue } } }
                 )
+                .disabled(!isEffectivelyOnline)
                 Divider()
                 preferenceToggleRow(
                     "Show line numbers",
@@ -266,6 +277,7 @@ struct SettingsView: View {
                     isOn: session.userPreferences?.codeBlockLineNumbers ?? false,
                     onChange: { newValue in Task { await savePreference { $0.codeBlockLineNumbers = newValue } } }
                 )
+                .disabled(!isEffectivelyOnline)
                 Divider()
                 preferenceToggleRow(
                     "Show comment marker",
@@ -273,6 +285,7 @@ struct SettingsView: View {
                     isOn: session.userPreferences?.showCommentMarker ?? false,
                     onChange: { newValue in Task { await savePreference { $0.showCommentMarker = newValue } } }
                 )
+                .disabled(!isEffectivelyOnline)
             }
 
             preferencesSubsection("Behavior") {
@@ -299,6 +312,7 @@ struct SettingsView: View {
                 Divider()
                 notificationBadgeRow
             }
+            .disabled(!isEffectivelyOnline)
 
             if let preferencesErrorMessage {
                 Text(preferencesErrorMessage)
@@ -309,6 +323,7 @@ struct SettingsView: View {
             preferencesSubsection("Danger") {
                 deleteAccountRow
             }
+            .disabled(!isEffectivelyOnline)
         }
         .frame(maxWidth: 480, alignment: .leading)
         .task { await refreshProfile() }
@@ -778,6 +793,20 @@ struct SettingsView: View {
 
     // MARK: - Helpers
 
+    /// Everything backed by a live `users.update`/`users.notifications*`
+    /// call (Profile's name/avatar, all of Preferences, all of
+    /// Notifications) shows this and disables its controls while offline —
+    /// there's nothing to optimistically apply here the way document edits
+    /// can be, and no offline queue for it (see `TODO.local.md`'s own
+    /// "things that actually require an internet connection" framing,
+    /// already applied to Share/Permissions/Search). Local-only settings
+    /// (Appearance, Offline Mode itself) are deliberately left enabled.
+    private var offlineSettingsHint: some View {
+        Text("You're offline — these settings need a connection to change.")
+            .font(.caption)
+            .foregroundStyle(.orange)
+    }
+
     private func labeledRow(_ label: String, _ value: String) -> some View {
         HStack {
             Text(label)