fix: restart development launcher after rebuilding

Makefile

@@ -10,7 +10,7 @@ build:
 	codesign --force --sign - $(APP)
 
 run: build
-	open $(APP)
+	swift Scripts/run.swift "$(APP)"
 
 test:
 	swift test

README.md

@@ -10,7 +10,7 @@ Requires macOS 14 or later and a Swift 6 toolchain (Xcode 16 or later).
 make run
 ```
 
-This builds a release executable, assembles an ad-hoc-signed application at `.build/Conjure.app`, and opens it through Launch Services. You can also open that app directly in Finder. The local signature is for development, not notarized distribution.
+This builds a release executable, assembles an ad-hoc-signed application at `.build/Conjure.app`, gracefully quits any running instance of that exact development bundle, and launches a fresh process through Launch Services. This ensures rebuilt code is loaded; simply opening an already-running app in Finder does not reload its executable. Other copies of Conjure are left running. The local signature is for development, not notarized distribution.
 
 ```sh
 make build   # Build the application without opening it.

Scripts/run.swift

@@ -0,0 +1,34 @@
+import AppKit
+
+func fail(_ message: String) -> Never {
+    FileHandle.standardError.write(Data("\(message)\n".utf8))
+    exit(1)
+}
+
+guard CommandLine.arguments.count == 2 else {
+    fail("Usage: swift Scripts/run.swift <Conjure.app>")
+}
+let target = URL(fileURLWithPath: CommandLine.arguments[1]).standardizedFileURL.resolvingSymlinksInPath()
+let running = NSRunningApplication.runningApplications(withBundleIdentifier: "dev.conjure.launcher")
+    .filter { $0.bundleURL?.resolvingSymlinksInPath().path == target.path }
+for app in running {
+    guard app.terminate() else { fail("Could not quit the existing Conjure instance.") }
+}
+for _ in 0..<100 {
+    if running.allSatisfy(\.isTerminated) { break }
+    // AppKit refreshes running-application state on the main run loop.
+    RunLoop.main.run(until: Date(timeIntervalSinceNow: 0.05))
+}
+guard running.allSatisfy(\.isTerminated) else {
+    fail("Conjure did not quit; the rebuilt app was not launched. Quit it and try again.")
+}
+
+let configuration = NSWorkspace.OpenConfiguration()
+configuration.createsNewApplicationInstance = true
+NSWorkspace.shared.openApplication(at: target, configuration: configuration) { app, error in
+    if let error { fail("Could not launch Conjure: \(error.localizedDescription)") }
+    guard let app else { fail("Launch Services did not return a running application.") }
+    print("Opened rebuilt Conjure (PID \(app.processIdentifier)).")
+    exit(0)
+}
+RunLoop.main.run()