feat(sidebar): add single-project display mode

packages/web/server/lib/opencode/DOCUMENTATION.md

@@ -207,7 +207,8 @@ Managed health failures are classified as `timeout`, `connection_refused`, `conn
   - `readSettingsFromDiskMigrated()`
   - `writeSettingsToDisk(settings)`
   - `persistSettings(changes)`
-  - Persistent permission auto-accept policy is stored under `permissionAutoAccept`; execution ownership lives in `lib/permission-auto-accept/`.
+- Persistent permission auto-accept policy is stored under `permissionAutoAccept`; execution ownership lives in `lib/permission-auto-accept/`.
+- Shared sidebar preferences are stored as validated top-level fields: `sidebarProjectDisplayMode`, `sidebarSessionGroupingMode`, `sidebarProjectSortOrder`, and `sidebarShowRecentSection`. Device-local picker selection and sticky-header state do not enter `settings.json`.
 
 ## Public exports (settings-helpers.js)
 - `createSettingsHelpers(dependencies)`: creates settings helper runtime for settings request/response shaping.

packages/web/server/lib/opencode/settings-helpers.js

@@ -29,6 +29,9 @@ export const createSettingsHelpers = (dependencies) => {
   const PWA_ORIENTATION_VALUES = new Set(['system', 'portrait', 'landscape']);
   const MOBILE_KEYBOARD_MODE_VALUES = new Set(['native', 'resize-content']);
   const TERMINAL_SHELL_VALUES = new Set(['auto', 'bash', 'zsh', 'sh', 'fish', 'pwsh', 'powershell', 'cmd', 'dash', 'ksh', 'nu']);
+  const SIDEBAR_PROJECT_DISPLAY_MODE_VALUES = new Set(['all', 'single']);
+  const SIDEBAR_SESSION_GROUPING_MODE_VALUES = new Set(['by-worktree', 'flat']);
+  const SIDEBAR_PROJECT_SORT_ORDER_VALUES = new Set(['manual', 'a-z', 'z-a', 'date-added', 'recent']);
   const HIDDEN_MODELS_MAX = 1024;
   const RECENT_EFFORTS_MAX_KEYS = 128;
   const RECENT_EFFORTS_MAX_VARIANTS_PER_KEY = 5;
@@ -243,6 +246,18 @@ export const createSettingsHelpers = (dependencies) => {
     if (typeof candidate.activeProjectId === 'string' && candidate.activeProjectId.length > 0) {
       result.activeProjectId = candidate.activeProjectId;
     }
+    if (SIDEBAR_PROJECT_DISPLAY_MODE_VALUES.has(candidate.sidebarProjectDisplayMode)) {
+      result.sidebarProjectDisplayMode = candidate.sidebarProjectDisplayMode;
+    }
+    if (SIDEBAR_SESSION_GROUPING_MODE_VALUES.has(candidate.sidebarSessionGroupingMode)) {
+      result.sidebarSessionGroupingMode = candidate.sidebarSessionGroupingMode;
+    }
+    if (SIDEBAR_PROJECT_SORT_ORDER_VALUES.has(candidate.sidebarProjectSortOrder)) {
+      result.sidebarProjectSortOrder = candidate.sidebarProjectSortOrder;
+    }
+    if (typeof candidate.sidebarShowRecentSection === 'boolean') {
+      result.sidebarShowRecentSection = candidate.sidebarShowRecentSection;
+    }
 
     if (Array.isArray(candidate.securityScopedBookmarks)) {
       result.securityScopedBookmarks = normalizeStringArray(candidate.securityScopedBookmarks);

packages/web/server/lib/opencode/settings-helpers.test.js

@@ -66,6 +66,28 @@ describe('settings helpers', () => {
     expect(helpers.sanitizeSettingsUpdate({ draftStartersVisible: 'false' })).toEqual({});
   });
 
+  it('sanitizes shared sidebar display preferences', () => {
+    const helpers = createTestHelpers();
+
+    expect(helpers.sanitizeSettingsUpdate({
+      sidebarProjectDisplayMode: 'single',
+      sidebarSessionGroupingMode: 'flat',
+      sidebarProjectSortOrder: 'z-a',
+      sidebarShowRecentSection: false,
+    })).toEqual({
+      sidebarProjectDisplayMode: 'single',
+      sidebarSessionGroupingMode: 'flat',
+      sidebarProjectSortOrder: 'z-a',
+      sidebarShowRecentSection: false,
+    });
+    expect(helpers.sanitizeSettingsUpdate({
+      sidebarProjectDisplayMode: 'grid',
+      sidebarSessionGroupingMode: 'project',
+      sidebarProjectSortOrder: 'random',
+      sidebarShowRecentSection: 'false',
+    })).toEqual({});
+  });
+
   it('accepts only booleans for wide chat layout', () => {
     const helpers = createTestHelpers();
 

packages/web/server/lib/opencode/settings-runtime.test.js

@@ -39,6 +39,24 @@ const createRuntime = async () => {
 };
 
 describe('settings runtime', () => {
+  it('round-trips shared sidebar preferences through settings.json', async () => {
+    const { runtime, settingsFilePath, cleanup } = await createRuntime();
+    const preferences = {
+      sidebarProjectDisplayMode: 'single',
+      sidebarSessionGroupingMode: 'flat',
+      sidebarProjectSortOrder: 'date-added',
+      sidebarShowRecentSection: false,
+    };
+    try {
+      await runtime.persistSettings(preferences);
+
+      await expect(runtime.readSettingsFromDisk()).resolves.toEqual(preferences);
+      await expect(fsPromises.readFile(settingsFilePath, 'utf8')).resolves.toBe(JSON.stringify(preferences, null, 2));
+    } finally {
+      await cleanup();
+    }
+  });
+
   it.skipIf(process.platform === 'win32')('writes settings with restrictive directory and file permissions', async () => {
     const { runtime, settingsFilePath, tempRoot, cleanup } = await createRuntime();
     try {