Rewrite shannoncoat as a native Swift menu-bar app

Replaces the original shannoncoat.sh entirely with in-process Swift. The
script stopped earning its keep once the rest went native, and being a
persistent process rather than a one-shot CLI is what later makes live
window tracking possible at all.

- ProfileStore: JSON config at ~/.shannoncoat/<name>.json (was hand-rolled
  YAML), with ~ expansion, paths relative to the config dir, and
  name/dir-collision validation in one place.
- ProcessInspector: sysctl(KERN_PROC_ALL/KERN_PROCARGS2) enumeration
  instead of shelling out to pgrep.
- ClaudeControl: launch via Process, focus via direct Accessibility calls
  (unhide, un-minimize, poll-for-window, AXRaise) instead of AppleScript,
  and a quit that respects Claude's own termination handling rather than
  unconditionally SIGKILLing after a flat 5s timeout.
- LiveState: NSWorkspace notification-driven state with no polling timer,
  so the menu bar reflects reality within about a second — including
  changes made outside the app entirely.
- ManageWindow: one non-modal window replacing what would otherwise be a
  string of separate popup alerts, with inline add/remove and directory
  pickers.
- LaunchAtLogin / UpdateChecker: SMAppService login-item toggle, and a
  minimal VERSION-file update check that alerts on a manual check and
  posts a quiet notification on the automatic one.

Also drops the standalone CLI in favour of GUI-only, and adds a
placeholder app icon drawn from vector shapes rather than composited on
top of Claude's own icon assets.

Claude Desktop is located at runtime rather than assumed: a path the user
picked previously, then /Applications, then a per-user ~/Applications
install, each accepted only if it actually contains the executable. If
none match, launching a profile asks the user to locate it once and
remembers the answer — a launch that silently does nothing gives them no
way to work out what's wrong.

Sources/UpdateChecker.swift

@@ -0,0 +1,90 @@
+// Deliberately minimal: fetch the raw VERSION file from `main` on GitHub
+// and compare semver to the bundled version. No silent binary-replacing
+// auto-update — that needs signing/notarization/an appcast server this
+// project doesn't have. A manual check shows an alert (an explicit action
+// that expects a response); the periodic automatic check instead posts a
+// quiet system notification, since that one wasn't asked for in the
+// moment.
+import Foundation
+import UserNotifications
+
+enum UpdateChecker {
+    enum Outcome {
+        case upToDate
+        case updateAvailable(version: String, url: URL)
+        case failed
+    }
+
+    private static let versionURL = URL(string: "https://raw.githubusercontent.com/bdeshi/shannoncoat/main/VERSION")!
+    private static let releaseURL = URL(string: "https://github.com/bdeshi/shannoncoat/releases/latest")!
+    private static let enabledDefaultsKey = "AutomaticUpdateCheckEnabled"
+    private static let lastCheckDefaultsKey = "LastUpdateCheckDate"
+    private static let checkInterval: TimeInterval = 24 * 60 * 60
+
+    static var automaticCheckEnabled: Bool {
+        get { UserDefaults.standard.object(forKey: enabledDefaultsKey) as? Bool ?? true }
+        set { UserDefaults.standard.set(newValue, forKey: enabledDefaultsKey) }
+    }
+
+    static var currentVersion: String {
+        guard let resourceURL = Bundle.main.resourceURL,
+              let contents = try? String(contentsOf: resourceURL.appendingPathComponent("VERSION"), encoding: .utf8)
+        else { return "unknown" }
+        return contents.trimmingCharacters(in: .whitespacesAndNewlines)
+    }
+
+    static func checkManually(completion: @escaping (Outcome) -> Void) {
+        fetchLatestVersion { latest in
+            guard let latest else { completion(.failed); return }
+            if isNewer(latest, than: currentVersion) {
+                completion(.updateAvailable(version: latest, url: releaseURL))
+            } else {
+                completion(.upToDate)
+            }
+        }
+    }
+
+    // Called once at launch; a no-op unless the toggle is on and it's been
+    // at least a day since the last check.
+    static func checkAutomaticallyIfDue() {
+        guard automaticCheckEnabled else { return }
+        let last = UserDefaults.standard.object(forKey: lastCheckDefaultsKey) as? Date ?? .distantPast
+        guard Date().timeIntervalSince(last) > checkInterval else { return }
+        UserDefaults.standard.set(Date(), forKey: lastCheckDefaultsKey)
+
+        fetchLatestVersion { latest in
+            guard let latest, isNewer(latest, than: currentVersion) else { return }
+            postAvailableNotification(version: latest)
+        }
+    }
+
+    private static func fetchLatestVersion(completion: @escaping (String?) -> Void) {
+        URLSession.shared.dataTask(with: versionURL) { data, _, _ in
+            let version = data.flatMap { String(data: $0, encoding: .utf8) }?
+                .trimmingCharacters(in: .whitespacesAndNewlines)
+            completion((version?.isEmpty == false) ? version : nil)
+        }.resume()
+    }
+
+    private static func isNewer(_ a: String, than b: String) -> Bool {
+        let av = a.split(separator: ".").compactMap { Int($0) }
+        let bv = b.split(separator: ".").compactMap { Int($0) }
+        for i in 0..<max(av.count, bv.count) {
+            let x = i < av.count ? av[i] : 0
+            let y = i < bv.count ? bv[i] : 0
+            if x != y { return x > y }
+        }
+        return false
+    }
+
+    private static func postAvailableNotification(version: String) {
+        let center = UNUserNotificationCenter.current()
+        center.requestAuthorization(options: [.alert]) { granted, _ in
+            guard granted else { return }
+            let content = UNMutableNotificationContent()
+            content.title = "shannoncoat \(version) is available"
+            content.body = "Click to view the release notes."
+            center.add(UNNotificationRequest(identifier: "shannoncoat-update-available", content: content, trigger: nil))
+        }
+    }
+}