Remove in-list spinner + add monitored-repos setting; bump to 2.3

- Remove the in-list loading wheel overlay; the landing page just shows the
  cached list or the 'No open PRs' screen.
- Add a 'Monitored repos' setting (Settings > Inbox) that limits the inbox to
  specific repos, cutting the number of API calls dramatically. Empty =
  monitor all accessible repos. Bump to 2.3.

GiteaPR/Settings/SettingsStore.swift

@@ -27,6 +27,12 @@ final class SettingsStore: ObservableObject {
         didSet { UserDefaults.standard.set(deleteBranchAfterMerge,
                                            forKey: "deleteBranchAfterMerge") }
     }
+    /// Repos to monitor for the inbox. Empty = monitor all accessible repos.
+    /// Stored as full names (e.g. "luis/config-nixos").
+    @Published var monitoredRepos: [String] {
+        didSet { UserDefaults.standard.set(monitoredRepos,
+                                           forKey: "monitoredRepos") }
+    }
 
     private init() {
         instanceURL = KeychainHelper.get("instanceURL") ?? "https://gitea.bueso.eu"
@@ -34,6 +40,7 @@ final class SettingsStore: ObservableObject {
         let raw = UserDefaults.standard.string(forKey: "mergeGateMode")
         mergeGateMode = MergeGateMode(rawValue: raw ?? "") ?? .warn
         deleteBranchAfterMerge = UserDefaults.standard.bool(forKey: "deleteBranchAfterMerge")
+        monitoredRepos = UserDefaults.standard.stringArray(forKey: "monitoredRepos") ?? []
     }
 
     var isConfigured: Bool {