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/settings.dart

@@ -0,0 +1,218 @@
+import 'dart:io';
+
+import 'package:flutter/foundation.dart';
+import 'package:yaml/yaml.dart';
+
+enum SettingsScope { app, project, ext }
+
+class SettingsStore extends ChangeNotifier {
+  SettingsStore({required this.appDir, this.projectDir});
+
+  final Directory appDir;
+  Directory? projectDir;
+
+  final Map<String, Object?> _appValues = <String, Object?>{};
+  final Map<String, Object?> _projectValues = <String, Object?>{};
+
+  Future<void> load() async {
+    _appValues
+      ..clear()
+      ..addAll(await _readFile(_appFile));
+    _projectValues.clear();
+    if (projectDir != null) {
+      _projectValues.addAll(await _readFile(_projectFile));
+    }
+    notifyListeners();
+  }
+
+  Future<void> setProjectDir(Directory? dir) async {
+    projectDir = dir;
+    _projectValues.clear();
+    if (dir != null) {
+      _projectValues.addAll(await _readFile(_projectFile));
+    }
+    notifyListeners();
+  }
+
+  File get _appFile => File('${appDir.path}/settings.yaml');
+  File get _projectFile => File('${projectDir!.path}/.clide/settings.yaml');
+
+  T? get<T>(String key) {
+    final v = _lookup(key);
+    if (v is T) return v;
+    if (T == int && v is num) return v.toInt() as T;
+    if (T == double && v is num) return v.toDouble() as T;
+    return null;
+  }
+
+  Object? _lookup(String key) {
+    switch (_scopeOf(key)) {
+      case SettingsScope.app:
+        return _appValues[key];
+      case SettingsScope.project:
+        return _projectValues[key];
+      case SettingsScope.ext:
+        // project overrides app for the same ext.* key
+        return _projectValues.containsKey(key)
+            ? _projectValues[key]
+            : _appValues[key];
+    }
+  }
+
+  Future<void> set<T>(String key, T value) async {
+    switch (_scopeOf(key)) {
+      case SettingsScope.app:
+        _appValues[key] = value;
+        await _writeFile(_appFile, _appValues);
+      case SettingsScope.project:
+        if (projectDir == null) {
+          throw StateError(
+              'Cannot set project-scoped key with no project open: $key');
+        }
+        _projectValues[key] = value;
+        await _writeFile(_projectFile, _projectValues);
+      case SettingsScope.ext:
+        // default: store under app until an ext manifest requests project scope
+        _appValues[key] = value;
+        await _writeFile(_appFile, _appValues);
+    }
+    notifyListeners();
+  }
+
+  Future<Map<String, Object?>> _readFile(File f) async {
+    try {
+      if (!await f.exists()) return <String, Object?>{};
+      final txt = await f.readAsString();
+      if (txt.trim().isEmpty) return <String, Object?>{};
+      final yaml = loadYaml(txt);
+      final out = <String, Object?>{};
+      if (yaml is Map) _flatten(yaml, '', out);
+      return out;
+    } catch (_) {
+      // On web (or in sandboxes where the path isn't writable) silently
+      // degrade to an empty in-memory catalog. `set` will no-op too.
+      return <String, Object?>{};
+    }
+  }
+
+  Future<void> _writeFile(File f, Map<String, Object?> flat) async {
+    try {
+      await f.parent.create(recursive: true);
+      await f.writeAsString(_emitYaml(_unflatten(flat)));
+    } catch (_) {
+      // Web / read-only sandbox: in-memory update remains valid, we
+      // just can't persist. Callers already called notifyListeners.
+    }
+  }
+
+  static SettingsScope _scopeOf(String key) {
+    if (key.startsWith('app.')) return SettingsScope.app;
+    if (key.startsWith('project.')) return SettingsScope.project;
+    if (key.startsWith('ext.')) return SettingsScope.ext;
+    throw ArgumentError(
+        'Settings key must start with app.|project.|ext.: "$key"');
+  }
+}
+
+void _flatten(Map src, String prefix, Map<String, Object?> into) {
+  src.forEach((k, v) {
+    final key = prefix.isEmpty ? '$k' : '$prefix.$k';
+    if (v is Map) {
+      _flatten(v, key, into);
+    } else if (v is YamlList) {
+      into[key] = v.toList();
+    } else {
+      into[key] = v;
+    }
+  });
+}
+
+Map<String, Object?> _unflatten(Map<String, Object?> flat) {
+  final root = <String, Object?>{};
+  flat.forEach((k, v) {
+    final parts = k.split('.');
+    var cursor = root;
+    for (var i = 0; i < parts.length - 1; i++) {
+      final next = cursor[parts[i]];
+      if (next is Map<String, Object?>) {
+        cursor = next;
+      } else {
+        final fresh = <String, Object?>{};
+        cursor[parts[i]] = fresh;
+        cursor = fresh;
+      }
+    }
+    cursor[parts.last] = v;
+  });
+  return root;
+}
+
+String _emitYaml(Object? value, {int indent = 0}) {
+  final buf = StringBuffer();
+  _emit(buf, value, indent);
+  return buf.toString();
+}
+
+void _emit(StringBuffer buf, Object? v, int indent) {
+  final pad = '  ' * indent;
+  if (v is Map) {
+    if (v.isEmpty) {
+      buf.writeln('{}');
+      return;
+    }
+    v.forEach((k, vv) {
+      buf.write('$pad$k:');
+      if (vv is Map && vv.isNotEmpty) {
+        buf.writeln();
+        _emit(buf, vv, indent + 1);
+      } else if (vv is List && vv.isNotEmpty) {
+        buf.writeln();
+        for (final item in vv) {
+          buf.write('$pad- ');
+          _emitScalar(buf, item);
+          buf.writeln();
+        }
+      } else {
+        buf.write(' ');
+        _emitScalar(buf, vv);
+        buf.writeln();
+      }
+    });
+    return;
+  }
+  _emitScalar(buf, v);
+  buf.writeln();
+}
+
+void _emitScalar(StringBuffer buf, Object? v) {
+  if (v == null) {
+    buf.write('null');
+  } else if (v is bool || v is num) {
+    buf.write(v);
+  } else if (v is String) {
+    if (_needsQuoting(v)) {
+      buf.write('"${v.replaceAll(r'\', r'\\').replaceAll('"', r'\"')}"');
+    } else {
+      buf.write(v);
+    }
+  } else if (v is List) {
+    buf.write('[');
+    for (var i = 0; i < v.length; i++) {
+      if (i > 0) buf.write(', ');
+      _emitScalar(buf, v[i]);
+    }
+    buf.write(']');
+  } else {
+    buf.write('"${v.toString()}"');
+  }
+}
+
+bool _needsQuoting(String s) {
+  if (s.isEmpty) return true;
+  if (RegExp(r'[:\#\n\r\t]').hasMatch(s)) return true;
+  if (s != s.trim()) return true;
+  const reserved = {'true', 'false', 'null', 'yes', 'no', 'on', 'off', '~'};
+  if (reserved.contains(s.toLowerCase())) return true;
+  if (num.tryParse(s) != null) return true;
+  return false;
+}