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/kernel/src/theme/palette.dart

@@ -0,0 +1,22 @@
+import 'dart:ui';
+
+import 'package:flutter/foundation.dart';
+
+@immutable
+class Palette {
+  const Palette(this._colors);
+  final Map<String, Color> _colors;
+
+  Color? lookup(String name) => _colors[name];
+  Iterable<String> get names => _colors.keys;
+
+  static Color? parseHex(String s) {
+    var v = s.trim();
+    if (v.startsWith('#')) v = v.substring(1);
+    if (v.length == 6) v = 'FF$v';
+    if (v.length != 8) return null;
+    final n = int.tryParse(v, radix: 16);
+    if (n == null) return null;
+    return Color(n);
+  }
+}