persist the chosen theme per repo across loads (T-293)

ThemeController.select() applied live but never persisted, so every restart reset
to the first bundled theme. Add wireThemePersistence (facade): on theme change
write app.theme (global default) + project.theme (the open repo's
.clide/settings.yaml); on settings change — notably when a repo opens and its
project values load — restore the most specific saved theme (project then app).
The name encodes the -hc variant so high-contrast persists; an unknown/removed
theme is ignored so a stale value can't wedge startup.

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

CHANGELOG.md

@@ -212,6 +212,11 @@ heading, and (b) bumping `pubspec.yaml` `version:` in the same commit.
 
 ### Fixed
 
+- **The chosen theme now persists across restarts**, per repo. Picking a theme
+  (status-bar switcher or Settings) writes it to the repo's
+  `.clide/settings.yaml` (and a global default), and reopening the repo restores
+  it — including the high-contrast variant. A removed theme falls back to the
+  default instead of resetting silently. (T-293)
 - Folded activity and agent-run cards in the Claude conversation now use the
   same bottom spacing as the prose cards around them, instead of sitting
   cramped 3px below the next card. (T-282)

lib/kernel/src/facade.dart

@@ -5,6 +5,7 @@ import 'package:clide/kernel/src/clipboard.dart';
 import 'package:clide/kernel/src/commands/keybindings.dart';
 import 'package:clide/kernel/src/keymap/keymap_service.dart';
 import 'package:clide/kernel/src/text_zoom.dart';
+import 'package:clide/kernel/src/theme/theme_persistence.dart';
 import 'package:clide/kernel/src/toast.dart';
 import 'package:clide/kernel/src/commands/palette.dart';
 import 'package:clide/kernel/src/commands/registry.dart';
@@ -158,6 +159,7 @@ class KernelServices {
     }
 
     final theme = ThemeController(bundled: bundledThemes);
+    wireThemePersistence(theme, settings);
     final panels = PanelRegistry();
     final arrangement = LayoutArrangement();
     final commands = CommandRegistry();

lib/kernel/src/theme/theme_persistence.dart

@@ -0,0 +1,40 @@
+/// Persist the chosen theme and restore it across loads (T-293).
+///
+/// clide runs a single live [ThemeController]; this bridges it to the
+/// [SettingsStore] so a choice survives a restart. On every theme change we
+/// write `app.theme` (the global last-used default) and, when a repo is open,
+/// `project.theme` in that repo's `.clide/settings.yaml`. Whenever the settings
+/// change — notably when a repo opens and its project values load — we restore
+/// the most specific saved theme: `project.theme`, else the global `app.theme`.
+/// The current name already encodes the high-contrast variant (`<base>-hc`), so
+/// the toggle persists for free. An unknown/removed theme name is ignored, so a
+/// stale value can't wedge startup.
+library;
+
+import 'dart:async';
+
+import 'package:clide/kernel/src/settings.dart';
+import 'package:clide/kernel/src/theme/controller.dart';
+
+void wireThemePersistence(ThemeController theme, SettingsStore settings) {
+  theme.addListener(() {
+    final name = theme.currentName;
+    // Global default — lets a brand-new / unthemed repo inherit the last choice.
+    if (settings.get<String>('app.theme') != name) {
+      unawaited(settings.set<String>('app.theme', name));
+    }
+    // Per-repo, when one is open.
+    if (settings.projectDir != null && settings.get<String>('project.theme') != name) {
+      unawaited(settings.set<String>('project.theme', name));
+    }
+  });
+
+  void restore() {
+    final saved = settings.get<String>('project.theme') ?? settings.get<String>('app.theme');
+    if (saved == null || saved == theme.currentName) return;
+    if (theme.available.any((d) => d.name == saved)) theme.select(saved);
+  }
+
+  settings.addListener(restore);
+  restore(); // apply the global default already loaded at boot
+}

test/kernel/src/theme_persistence_test.dart

@@ -0,0 +1,106 @@
+import 'dart:io';
+
+import 'package:clide/kernel/kernel.dart';
+import 'package:clide/kernel/src/theme/theme_persistence.dart';
+import 'package:flutter/widgets.dart' show Color;
+import 'package:flutter_test/flutter_test.dart';
+
+ThemeDefinition _def(String name) => ThemeDefinition(
+      name: name,
+      displayName: name,
+      dark: true,
+      palette: Palette(const {
+        'primary': Color(0xFF00A3D2),
+        'accent': Color(0xFFFA5F8B),
+        'background': Color(0xFF21262F),
+        'surface': Color(0xFF393E48),
+        'panel': Color(0xFF292E38),
+        'foreground': Color(0xFFE2E8F5),
+        'success': Color(0xFF00AB9A),
+        'warning': Color(0xFFD08447),
+        'error': Color(0xFFF06C6F),
+      }),
+    );
+
+void main() {
+  group('wireThemePersistence (T-293)', () {
+    late Directory appTmp;
+    late Directory repoTmp;
+    late SettingsStore settings;
+    late ThemeController theme;
+
+    setUp(() async {
+      appTmp = await Directory.systemTemp.createTemp('clide_theme_app_');
+      repoTmp = await Directory.systemTemp.createTemp('clide_theme_repo_');
+      settings = SettingsStore(appDir: appTmp);
+      await settings.load();
+      theme = ThemeController(bundled: [_def('summer-night'), _def('forest'), _def('paper'), _def('paper-hc')]);
+      wireThemePersistence(theme, settings);
+    });
+
+    tearDown(() async {
+      await pumpEventQueue(); // flush any in-flight unawaited set() file writes
+      settings.dispose();
+      theme.dispose();
+      for (final d in [appTmp, repoTmp]) {
+        if (await d.exists()) {
+          try {
+            await d.delete(recursive: true);
+          } catch (_) {}
+        }
+      }
+    });
+
+    test('selecting with no repo open persists app.theme (global default)', () async {
+      theme.select('forest');
+      expect(settings.get<String>('app.theme'), 'forest');
+      expect(settings.get<String>('project.theme'), isNull);
+    });
+
+    test('selecting with a repo open persists project.theme into that repo', () async {
+      await settings.setProjectDir(repoTmp);
+      theme.select('forest');
+      expect(settings.get<String>('project.theme'), 'forest');
+      await pumpEventQueue(); // let the unawaited file write flush
+      expect(await File('${repoTmp.path}/.clide/settings.yaml').exists(), isTrue);
+    });
+
+    test('the high-contrast variant persists (the name encodes -hc)', () async {
+      theme.select('paper-hc');
+      expect(settings.get<String>('app.theme'), 'paper-hc');
+    });
+
+    test('opening a repo restores project.theme over the global app.theme', () async {
+      await settings.set<String>('app.theme', 'forest');
+      await File('${repoTmp.path}/.clide/settings.yaml').create(recursive: true);
+      await File('${repoTmp.path}/.clide/settings.yaml').writeAsString('project:\n  theme: paper\n');
+
+      await settings.setProjectDir(repoTmp); // loads project values + notifies → restore
+
+      expect(theme.currentName, 'paper');
+    });
+
+    test('restores the global app.theme at wiring time (boot)', () async {
+      await File('${appTmp.path}/settings.yaml').writeAsString('app:\n  theme: forest\n');
+      final s2 = SettingsStore(appDir: appTmp);
+      await s2.load();
+      final t2 = ThemeController(bundled: [_def('summer-night'), _def('forest')]);
+      expect(t2.currentName, 'summer-night'); // bundled.first before wiring
+
+      wireThemePersistence(t2, s2);
+
+      expect(t2.currentName, 'forest'); // restored from app.theme
+      s2.dispose();
+      t2.dispose();
+    });
+
+    test('an unknown saved theme is ignored (no throw, keeps current)', () async {
+      await File('${repoTmp.path}/.clide/settings.yaml').create(recursive: true);
+      await File('${repoTmp.path}/.clide/settings.yaml').writeAsString('project:\n  theme: gone-theme\n');
+
+      await settings.setProjectDir(repoTmp);
+
+      expect(theme.currentName, 'summer-night'); // unchanged
+    });
+  });
+}