Add project save and load controls

Sources/GrowthLapse/ContentView.swift

@@ -39,6 +39,11 @@ struct ContentView: View {
                     ) {
                         selectOutputFile()
                     }
+
+                    Button("Projekt laden") {
+                        selectProjectFile()
+                    }
+                    .help("Lädt eine gespeicherte .growthlapse-project.json, inklusive Segmentfenstern und Variantenwahl.")
                 }
                 .disabled(processor.state.isRunning)
 
@@ -365,6 +370,12 @@ struct ContentView: View {
                 .disabled(processor.state.isRunning || !project.clips.contains(where: \.needsRender))
                 .help("Rendert nur geänderte normalisierte Clips neu und baut danach das finale Video erneut.")
 
+                Button("Projekt speichern") {
+                    processor.saveCurrentProject()
+                }
+                .disabled(processor.state.isRunning)
+                .help("Speichert die aktuelle Nachbearbeitung in die .growthlapse-project.json neben der Output-Datei. Segmentänderungen werden zusätzlich automatisch gespeichert.")
+
                 Button("Ergebnis bestätigen") {
                     processor.confirmProjectAndDeleteCache()
                 }
@@ -619,6 +630,23 @@ struct ContentView: View {
         }
     }
 
+    private func selectProjectFile() {
+        let panel = NSOpenPanel()
+        panel.title = "GrowthLapse-Projekt laden"
+        panel.canChooseFiles = true
+        panel.canChooseDirectories = false
+        panel.allowsMultipleSelection = false
+        panel.allowedContentTypes = [.json]
+        panel.directoryURL = settings.outputFile?.deletingLastPathComponent()
+        if panel.runModal() == .OK,
+           let url = panel.url,
+           let project = processor.loadProject(from: url) {
+            settings.outputFile = project.outputFileURL
+            settings.inputFolder = project.clips.first?.sourceURL.deletingLastPathComponent()
+            selectedClipID = project.clips.first?.id
+        }
+    }
+
     private func selectExecutable(title: String, onSelect: (URL) -> Void) {
         let panel = NSOpenPanel()
         panel.title = title

Sources/GrowthLapse/VideoProcessor.swift

@@ -137,6 +137,42 @@ final class VideoProcessor: ObservableObject {
         saveProject(reordered)
     }
 
+    func saveCurrentProject() {
+        guard let project else {
+            appendLog("Kein Projekt zum Speichern geladen.")
+            return
+        }
+        saveProject(project)
+        appendLog("Projekt gespeichert: \(GrowthLapseProject.url(for: project.outputFileURL).path)")
+    }
+
+    func loadProject(from url: URL) -> GrowthLapseProject? {
+        do {
+            let data = try Data(contentsOf: url)
+            var loadedProject = try JSONDecoder().decode(GrowthLapseProject.self, from: data)
+            loadedProject.clips = loadedProject.clips.map { clip in
+                var updated = clip
+                if !FileManager.default.fileExists(atPath: updated.normalizedClipPath) {
+                    updated.needsRender = true
+                }
+                return updated
+            }
+            project = loadedProject
+            state = .finished(loadedProject.outputFileURL)
+            progress = 1
+            progressText = "Projekt geladen"
+            appendLog("Projekt geladen: \(url.path)")
+            if loadedProject.clips.contains(where: \.needsRender) {
+                appendLog("Hinweis: Einige Cache-Clips fehlen und werden beim nächsten Render neu erzeugt.")
+            }
+            return loadedProject
+        } catch {
+            state = .failed("Projekt konnte nicht geladen werden: \(error.localizedDescription)")
+            appendLog("Fehler: Projekt konnte nicht geladen werden: \(error.localizedDescription)")
+            return nil
+        }
+    }
+
     func confirmProjectAndDeleteCache() {
         guard let project else {
             return