feat: add TextInserter with clipboard restore and PassthroughCleaner

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

Sources/SstCore/PassthroughCleaner.swift

@@ -0,0 +1,7 @@
+public struct PassthroughCleaner: Cleaner {
+    public init() {}
+
+    public func clean(_ text: String, context: CleaningContext) async throws -> String {
+        text
+    }
+}

Sources/SstCore/SystemPasteboard.swift

@@ -0,0 +1,65 @@
+import AppKit
+import ApplicationServices
+
+public struct SystemPasteboard: PasteboardProviding {
+    public init() {}
+
+    public func readItems() -> [PasteboardItem] {
+        (NSPasteboard.general.pasteboardItems ?? []).map { item in
+            var dict: PasteboardItem = [:]
+            for type in item.types {
+                if let data = item.data(forType: type) { dict[type.rawValue] = data }
+            }
+            return dict
+        }
+    }
+
+    public func writeString(_ text: String) {
+        let pasteboard = NSPasteboard.general
+        pasteboard.clearContents()
+        pasteboard.setString(text, forType: .string)
+    }
+
+    public func writeItems(_ items: [PasteboardItem]) {
+        let pasteboard = NSPasteboard.general
+        pasteboard.clearContents()
+        let restored = items.map { dict -> NSPasteboardItem in
+            let item = NSPasteboardItem()
+            for (type, data) in dict { item.setData(data, forType: NSPasteboard.PasteboardType(type)) }
+            return item
+        }
+        if !restored.isEmpty { pasteboard.writeObjects(restored) }
+    }
+}
+
+public struct CGEventPaster: KeystrokePosting {
+    public enum PasteError: Error, LocalizedError {
+        case accessibilityDenied
+        case eventCreationFailed
+
+        public var errorDescription: String? {
+            switch self {
+            case .accessibilityDenied:
+                "Geen Accessibility-rechten: tekst staat op het klembord, plak zelf met ⌘V."
+            case .eventCreationFailed:
+                "Kon het plak-event niet aanmaken: tekst staat op het klembord."
+            }
+        }
+    }
+
+    public init() {}
+
+    public func postPaste() throws {
+        guard AXIsProcessTrusted() else { throw PasteError.accessibilityDenied }
+        let source = CGEventSource(stateID: .combinedSessionState)
+        let vKey: CGKeyCode = 0x09
+        guard
+            let down = CGEvent(keyboardEventSource: source, virtualKey: vKey, keyDown: true),
+            let up = CGEvent(keyboardEventSource: source, virtualKey: vKey, keyDown: false)
+        else { throw PasteError.eventCreationFailed }
+        down.flags = .maskCommand
+        up.flags = .maskCommand
+        down.post(tap: .cgAnnotatedSessionEventTap)
+        up.post(tap: .cgAnnotatedSessionEventTap)
+    }
+}

Sources/SstCore/TextInserter.swift

@@ -0,0 +1,39 @@
+import Foundation
+
+public typealias PasteboardItem = [String: Data]
+
+public protocol PasteboardProviding {
+    func readItems() -> [PasteboardItem]
+    func writeString(_ text: String)
+    func writeItems(_ items: [PasteboardItem])
+}
+
+public protocol KeystrokePosting {
+    func postPaste() throws
+}
+
+public struct TextInserter: TextInserting {
+    private let pasteboard: PasteboardProviding
+    private let paster: KeystrokePosting
+    private let restoreDelay: Duration
+
+    public init(
+        pasteboard: PasteboardProviding,
+        paster: KeystrokePosting,
+        restoreDelay: Duration = .milliseconds(150)
+    ) {
+        self.pasteboard = pasteboard
+        self.paster = paster
+        self.restoreDelay = restoreDelay
+    }
+
+    public func insert(_ text: String) async throws {
+        let saved = pasteboard.readItems()
+        pasteboard.writeString(text)
+        // On failure the text deliberately stays on the clipboard.
+        try paster.postPaste()
+        // Give the target app time to read the clipboard before restoring it.
+        try await Task.sleep(for: restoreDelay)
+        pasteboard.writeItems(saved)
+    }
+}