fix(sidebar): Unassigned chip resolves child projects through reference rows

The chip check now reuses the ancestor map built by _partitionSidebarSessionRows,
so a child whose project parent is only a hidden reference row is not counted
as unassigned. Document project inheritance for subagent sessions in README.

README.md

@@ -220,7 +220,7 @@ If an AI assistant is helping with install, reinstall, bootstrap, provider setup
 - Session actions via `⋯` dropdown per session — pin, move to project, archive, duplicate, delete
 - Pin/star sessions to the top of the sidebar (gold indicator)
 - Archive sessions (hide without deleting, toggle to show)
-- Session projects -- named groups with colors for organizing sessions
+- Session projects -- named groups with colors for organizing sessions; delegated subagent sessions have no project of their own and follow their nearest ancestor's project in the project filter and the Unassigned chip
 - Session tags -- add #tag to titles for colored chips and click-to-filter
 - Grouped by Today / Yesterday / Earlier in the sidebar (collapsible date groups)
 - Download as Markdown transcript, full JSON export, or import from JSON

static/sessions.js

@@ -7622,6 +7622,11 @@ function _sidebarRowsById(rows){
   return byId;
 }
 
+// True when any row resolves to no project, using the filter's own ancestor map.
+function _sidebarHasUnprojectedRows(rows, rowsById){
+  return rows.some(s=>!_sidebarProjectIdForRow(s, rowsById));
+}
+
 function _partitionSidebarSessionRows(allMatched, activeSidForSidebar){
   const rowsById=_sidebarRowsById([allMatched, typeof _sidebarReferenceSessions!=='undefined'?_sidebarReferenceSessions:null]);
   let cliSessionCount=0;
@@ -7670,6 +7675,7 @@ function _partitionSidebarSessionRows(allMatched, activeSidForSidebar){
     cliReferenceRaw,
     webuiSessionsRaw,
     cliSessionsRaw,
+    rowsById,
   };
 }
 
@@ -7797,6 +7803,7 @@ function renderSessionListFromCache(){
     cliReferenceRaw,
     webuiSessionsRaw,
     cliSessionsRaw,
+    rowsById,
   }=_partitionSidebarSessionRows(allMatched, activeSidForSidebar);
   const referenceRaw=_sessionSourceFilter==='cli'?cliReferenceRaw:webuiReferenceRaw;
   const isCliView=_sessionSourceFilter==='cli';
@@ -7871,8 +7878,7 @@ function renderSessionListFromCache(){
   }
   // Project filter bar — show when there are real projects OR there are
   // unassigned sessions (so the Unassigned chip has something to filter to).
-  const profileRowsById=_sidebarRowsById([profileFiltered]);
-  const hasUnprojected=profileFiltered.some(s=>!_sidebarProjectIdForRow(s, profileRowsById));
+  const hasUnprojected=_sidebarHasUnprojectedRows(profileFiltered, rowsById);
   if(_allProjects.length>0||hasUnprojected){
     const bar=document.createElement('div');
     bar.className='project-bar';

tests/test_sidebar_unassigned_filter.py

@@ -76,7 +76,7 @@ def test_unassigned_chip_only_shown_when_relevant():
     — though that's vanishingly rare).
     """
     js = _js()
-    assert "const hasUnprojected=profileFiltered.some(s=>!_sidebarProjectIdForRow(s, profileRowsById));" in js, (
+    assert "const hasUnprojected=_sidebarHasUnprojectedRows(profileFiltered, rowsById);" in js, (
         "The render function must compute whether unassigned sessions exist"
     )
     assert "if(_allProjects.length>0||hasUnprojected){" in js, (

tests/test_subagent_project_filter.py

@@ -44,7 +44,7 @@ global._sessionSourceFilter = 'webui';
 for (const fn of ['_isSessionLocallyStreaming','_hasPendingUserMessageSignal','_isSessionEffectivelyStreaming',
   '_isChildSession','_isForkWithResolvableParent','_sessionLineageKey','_sidebarLineageKeyForRow',
   '_collapseSessionLineageForSidebar','_attachChildSessionsToSidebarRows','_sessionAttentionState',
-  '_sidebarRowHasVisibleMessages','_sidebarProjectIdForRow','_sidebarRowsById',
+  '_sidebarRowHasVisibleMessages','_sidebarProjectIdForRow','_sidebarRowsById','_sidebarHasUnprojectedRows',
   '_partitionSidebarSessionRows','_scopedSidebarReferenceRows','_renderSidebarRowsFromRawSessions']) {
   eval.call(global, extractFunc(fn));
 }
@@ -115,4 +115,18 @@ console.log(JSON.stringify({raw: rows.raw, scoped}));
 
 
 def test_unassigned_chip_ignores_subagents_of_project_parents():
-    assert "const hasUnprojected=profileFiltered.some(s=>!_sidebarProjectIdForRow(s, profileRowsById));" in SESSIONS_JS
+    out = _run("console.log(JSON.stringify(_sidebarHasUnprojectedRows([parent, child], _sidebarRowsById([[parent, child]]))));")
+    assert out is False
+
+
+def test_unassigned_chip_uses_reference_parent():
+    """A child whose project parent is only a reference row is not unassigned."""
+    out = _run("""
+global._sidebarReferenceSessions = [parent];
+global._activeProject = null;
+const part = _partitionSidebarSessionRows([child], null);
+console.log(JSON.stringify({has: _sidebarHasUnprojectedRows(part.profileFiltered, part.rowsById),
+  unassigned: render(NO_PROJECT_FILTER, [child]).raw}));
+""")
+    assert out["unassigned"] == []
+    assert out["has"] is False