feat(web): sidebar group polish — even hover geometry, folder open/close icons, group pinning (#35)

Co-authored-by: Alice <alice@prismshadow.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

packages/web/src/lib/session-grouping.ts

@@ -89,3 +89,21 @@ export function groupSessionsByWorkspace(sessions: SessionInfo[]): WorkspaceGrou
   });
   return groups;
 }
+
+/**
+ * Stable pinned-first partition for sidebar groups: items whose key is in `pinned`
+ * come first, each partition preserving the input order (recency for Workspace
+ * groups, the configured order for Agents). Pure and mode-agnostic — callers pass
+ * the key extractor; pinned keys with no matching item are simply ignored.
+ */
+export function pinnedFirst<T>(
+  items: readonly T[],
+  keyOf: (item: T) => string,
+  pinned: ReadonlySet<string>,
+): T[] {
+  if (pinned.size === 0) return [...items];
+  const pin: T[] = [];
+  const rest: T[] = [];
+  for (const item of items) (pinned.has(keyOf(item)) ? pin : rest).push(item);
+  return [...pin, ...rest];
+}

packages/web/src/lib/strings-en.ts

@@ -21,6 +21,8 @@ export const en: Strings = {
     expandSidebar: "Expand sidebar",
     collapseGroup: "Collapse",
     expandGroup: "Expand",
+    pinGroup: "Pin group",
+    unpinGroup: "Unpin group",
   },
 
   settings: {

packages/web/src/lib/strings.ts

@@ -23,6 +23,8 @@ export const zh = {
     expandSidebar: "展开侧栏",
     collapseGroup: "折叠",
     expandGroup: "展开",
+    pinGroup: "置顶分组",
+    unpinGroup: "取消置顶",
   },
 
   settings: {