Fix Accessibility text capture failing system-wide

AXUIElementCreateSystemWide() returns kAXErrorCannotComplete (-25204) for
a background/menu-bar app on recent macOS, so the focused-element read
returned nil and GrammaGem recognised no text or text areas in any app.
Add AX.focusedElement(), which falls back to the frontmost app's PID-based
AX element (reliable from an accessory process), and route TextCapture's
selected-text and focused-field reads through it.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Sources/GrammaGem/System/AXSupport.swift

@@ -1,4 +1,5 @@
 import Foundation
+import AppKit
 import ApplicationServices
 
 /// Safe Accessibility helpers shared across the System layer.
@@ -36,4 +37,29 @@ enum AX {
     static func setMessagingTimeout(_ element: AXUIElement, _ seconds: Float) {
         AXUIElementSetMessagingTimeout(element, seconds)
     }
+
+    /// The currently-focused UI element across the system — robust to the
+    /// system-wide element failing.
+    ///
+    /// On recent macOS, `AXUIElementCreateSystemWide()` returns
+    /// `kAXErrorCannotComplete` (-25204) for *every* query made by a background /
+    /// accessory process (which is exactly what a menu-bar app like GrammaGem is).
+    /// When that happens the system-wide focused-element read yields nil and the
+    /// app "sees" no text or text fields at all. Resolving the focused element
+    /// through the **frontmost application's** own AX element works reliably in
+    /// that context, so we prefer the system-wide read (one IPC hop, correct on
+    /// OSes where it works) and transparently fall back to the per-app read.
+    static func focusedElement() -> AXUIElement? {
+        let systemWide = AXUIElementCreateSystemWide()
+        setMessagingTimeout(systemWide, 0.5)
+        if let element = copyElement(systemWide, kAXFocusedUIElementAttribute as String) {
+            return element
+        }
+        guard let pid = NSWorkspace.shared.frontmostApplication?.processIdentifier else {
+            return nil
+        }
+        let axApp = AXUIElementCreateApplication(pid)
+        setMessagingTimeout(axApp, 0.5)
+        return copyElement(axApp, kAXFocusedUIElementAttribute as String)
+    }
 }

Sources/GrammaGem/System/TextCapture.swift

@@ -53,9 +53,7 @@ final class TextCapture {
 
     private func captureViaAccessibility() -> Capture? {
         guard AXIsProcessTrusted() else { return nil }
-        let systemWide = AXUIElementCreateSystemWide()
+        guard let focused = AX.focusedElement() else { return nil }
-
-        guard let focused = AX.copyElement(systemWide, kAXFocusedUIElementAttribute) else { return nil }
 
         var valueRef: CFTypeRef?
         guard AXUIElementCopyAttributeValue(
@@ -93,8 +91,7 @@ final class TextCapture {
     /// The full text value of the focused element (not just the selection).
     func focusedFieldText() -> (text: String, element: AXUIElement)? {
         guard AXIsProcessTrusted() else { return nil }
-        let systemWide = AXUIElementCreateSystemWide()
+        guard let focused = AX.focusedElement() else { return nil }
-        guard let focused = AX.copyElement(systemWide, kAXFocusedUIElementAttribute) else { return nil }
 
         // Only treat genuine editable text roles as fixable, so we don't report
         // "nothing selected" failures on sliders/steppers/custom controls.