Phase 4: opt-in accessibility service (screen text dump, tap)

app/src/main/java/io/github/abrarul/modularai/service/AgentAccessibilityService.kt

@@ -0,0 +1,41 @@
+package io.github.abrarul.modularai.service
+
+import android.accessibilityservice.AccessibilityService
+import android.accessibilityservice.GestureDescription
+import android.graphics.Path
+import android.view.accessibility.AccessibilityEvent
+import android.view.accessibility.AccessibilityNodeInfo
+
+/**
+ * Off until the user enables it in Android Settings > Accessibility. It reads nothing on its own;
+ * it only answers the explicit console commands `screen` and `tap`.
+ */
+class AgentAccessibilityService : AccessibilityService() {
+
+    override fun onServiceConnected() { instance = this }
+    override fun onAccessibilityEvent(event: AccessibilityEvent?) {}
+    override fun onInterrupt() {}
+    override fun onDestroy() { if (instance === this) instance = null; super.onDestroy() }
+
+    fun dumpText(): String {
+        val sb = StringBuilder()
+        fun walk(n: AccessibilityNodeInfo?, depth: Int) {
+            if (n == null || depth > 40) return
+            val t = n.text ?: n.contentDescription
+            if (!t.isNullOrBlank()) sb.append("  ".repeat(depth)).append(t).append('\n')
+            for (i in 0 until n.childCount) walk(n.getChild(i), depth + 1)
+        }
+        walk(rootInActiveWindow, 0)
+        return sb.toString()
+    }
+
+    fun tap(x: Float, y: Float): Boolean {
+        val path = Path().apply { moveTo(x, y) }
+        val g = GestureDescription.Builder().addStroke(GestureDescription.StrokeDescription(path, 0, 50)).build()
+        return dispatchGesture(g, null, null)
+    }
+
+    companion object {
+        @Volatile var instance: AgentAccessibilityService? = null
+    }
+}