dissolve app/ into repo root (D-056)

Single Flutter package at the repo root. All code, tests, assets,
and platform directories moved from app/ to root. Package renamed
from clide_app to clide — all imports rewritten. Merged pubspec
combines core (ffi) and app (flutter, yaml, xterm) dependencies.
Makefile simplified: no APP_PRESENT conditionals, no cd, no daemon
lifecycle. 317 tests pass.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

lib/widgets/src/icons/plug.dart

@@ -0,0 +1,31 @@
+import 'package:clide/widgets/src/clide_icon.dart';
+import 'package:flutter/widgets.dart';
+
+/// Plug-shaped connection icon. Used by the ipc-status statusbar item
+/// and by future connection-state affordances.
+class PlugIcon extends ClideIconPainter {
+  const PlugIcon();
+
+  @override
+  void paint(Canvas canvas, Color color) {
+    final p = Paint()
+      ..color = color
+      ..style = PaintingStyle.stroke
+      ..strokeWidth = 0.10
+      ..strokeCap = StrokeCap.round;
+    // body
+    final body = Path()
+      ..moveTo(0.30, 0.30)
+      ..lineTo(0.60, 0.30)
+      ..lineTo(0.60, 0.55)
+      ..arcToPoint(const Offset(0.30, 0.55),
+          radius: const Radius.circular(0.15), clockwise: false)
+      ..close();
+    canvas.drawPath(body, p);
+    // cord
+    canvas.drawLine(const Offset(0.45, 0.60), const Offset(0.45, 0.88), p);
+    // prongs
+    canvas.drawLine(const Offset(0.38, 0.18), const Offset(0.38, 0.30), p);
+    canvas.drawLine(const Offset(0.52, 0.18), const Offset(0.52, 0.30), p);
+  }
+}