Keep main workspace first in project groups (#3178)

Co-authored-by: Jinwoo-H <jinwoo0825@gmail.com>

src/renderer/src/components/sidebar/worktree-list-groups.test.ts

@@ -638,6 +638,39 @@ describe('buildRows project grouping order', () => {
     ])
   })
 
+  it('keeps the main workspace first inside its project group', () => {
+    const main = {
+      ...wA,
+      id: 'wt-a-main',
+      displayName: 'main',
+      isMainWorktree: true
+    }
+    const freshChild = {
+      ...wA,
+      id: 'wt-a-fresh-child',
+      displayName: 'fresh-child',
+      isMainWorktree: false
+    }
+    const rows = buildRows(
+      'repo',
+      [freshChild, wB, main],
+      map,
+      null,
+      new Set(),
+      undefined,
+      undefined,
+      'visible-worktree-order'
+    )
+
+    expect(rows).toMatchObject([
+      { type: 'header', key: 'repo:repo-a' },
+      { type: 'item', worktree: { id: 'wt-a-main' } },
+      { type: 'item', worktree: { id: 'wt-a-fresh-child' } },
+      { type: 'header', key: 'repo:repo-b' },
+      { type: 'item', worktree: { id: 'wt-b' } }
+    ])
+  })
+
   it('keeps repoOrder for manual project group ordering', () => {
     const repoOrder = new Map([
       [repoB.id, 0],

src/renderer/src/components/sidebar/worktree-list-groups.ts

@@ -381,6 +381,16 @@ function appendWorktreeRows(
   }
 }
 
+function orderMainWorktreeFirst(worktrees: Worktree[]): Worktree[] {
+  const mainWorktrees = worktrees.filter((worktree) => worktree.isMainWorktree)
+  if (mainWorktrees.length === 0) {
+    return worktrees
+  }
+  // Why: project groups are scanned by repo; keep the repo's canonical
+  // workspace anchored even when dynamic sorts rank a child workspace first.
+  return [...mainWorktrees, ...worktrees.filter((worktree) => !worktree.isMainWorktree)]
+}
+
 /**
  * Build the flat row list consumed by the virtualizer.
  * Extracted here to keep WorktreeList.tsx under the line-count lint limit.
@@ -593,7 +603,8 @@ export function buildRows(
             result.push(buildImportedWorktreesCardRow(candidate, 'repo-group'))
           }
         }
-        appendWorktreeRows(result, group.items, repoMap, lineageById, worktreeMap, {
+        const items = groupBy === 'repo' ? orderMainWorktreeFirst(group.items) : group.items
+        appendWorktreeRows(result, items, repoMap, lineageById, worktreeMap, {
           nestLineage,
           collapsedGroups
         })