fix(graph-tree): class_code column, SubjectClass expansion handler

- _query_teacher_classes: fix code -> class_code (Supabase column name), add section_id param
- _build_timetable_section: tag class nodes with section_id=timetable
- _build_classes_section: tag class nodes with section_id=classes
- SubjectClass handler: section=timetable -> taught_lessons for class; section=classes -> enrolled students

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

routers/database/tools/graph_tree_router.py

@@ -166,7 +166,9 @@ def _query_month_days(month_uuid: str) -> List[Dict]:
         return []
 
 
-def _query_teacher_classes(user_id: str, institute_id: str, institute_db: str) -> List[Dict]:
+def _query_teacher_classes(
+    user_id: str, institute_id: str, institute_db: str, section_id: str = ""
+) -> List[Dict]:
     """Query classes for a teacher or student from Supabase (source of truth)."""
     try:
         sb = _sb()
@@ -192,7 +194,7 @@ def _query_teacher_classes(user_id: str, institute_id: str, institute_db: str) -
             return []
         classes = (
             sb.supabase.table("classes")
-            .select("id, name, code, subject")
+            .select("id, name, class_code, subject")
             .in_("id", all_ids)
             .eq("institute_id", institute_id)
             .eq("is_active", True)
@@ -203,15 +205,24 @@ def _query_teacher_classes(user_id: str, institute_id: str, institute_db: str) -
         result = []
         for c in classes:
             role = "teacher" if c["id"] in teacher_class_ids else "student"
-            result.append({
+            label = c.get("class_code") or c.get("name") or "Class"
+            node: Dict = {
                 "neo4j_node_id": c["id"],
-                "label": c.get("name") or "Class",
+                "label": label,
                 "node_type": "SubjectClass",
                 "neo4j_db_name": institute_db,
                 "is_section": False,
                 "has_children": True,
-                "neo4j_props": {"role": role, "subject": c.get("subject") or ""},
+                "neo4j_props": {
-            })
+                    "role": role,
+                    "subject": c.get("subject") or "",
+                    "name": c.get("name") or "",
+                    "class_code": c.get("class_code") or "",
+                },
+            }
+            if section_id:
+                node["section_id"] = section_id
+            result.append(node)
         return result
     except Exception as e:
         logger.warning(f"Could not query classes for user {user_id}: {e}")
@@ -278,7 +289,7 @@ def _build_timetable_section(user_id: str, institute_id: Optional[str], institut
                 tt = rec["tt"]
                 tt_uuid = tt["uuid_string"]
                 # Load classes from Supabase (source of truth)
-                classes = _query_teacher_classes(user_id, institute_id, institute_db)
+                classes = _query_teacher_classes(user_id, institute_id, institute_db, section_id="timetable")
                 return {
                     **_section("timetable", "My Timetable", institute_db, "populated",
                                has_children=True, children=classes if classes else None),
@@ -296,7 +307,7 @@ def _build_classes_section(user_id: str, institute_id: Optional[str], institute_
     if not institute_db or not institute_id:
         return _section("classes", "My Classes", "", "no_school")
 
-    classes = _query_teacher_classes(user_id, institute_id, institute_db)
+    classes = _query_teacher_classes(user_id, institute_id, institute_db, section_id="classes")
     if classes:
         return _section("classes", "My Classes", institute_db, "populated",
                         has_children=True, children=classes)
@@ -451,6 +462,84 @@ def _get_children_for_node(
                 logger.warning(f"TeacherTimetable term children failed: {e}")
                 return []
 
+    # SubjectClass — expand to taught lessons (timetable context) or members (classes context)
+    if node_type == "SubjectClass":
+        class_id = neo4j_node_id  # Supabase class UUID
+        try:
+            sb = _sb()
+            if section_id == "timetable" and user_email:
+                # Resolve teacher profile_id from email
+                prof = sb.supabase.table("profiles").select("id").eq("email", user_email).single().execute()
+                teacher_id = (prof.data or {}).get("id")
+                if teacher_id:
+                    lessons = (
+                        sb.supabase.table("taught_lessons")
+                        .select("id, date, period_code, class_name, subject")
+                        .eq("class_id", class_id)
+                        .eq("teacher_profile_id", teacher_id)
+                        .order("date")
+                        .order("period_code")
+                        .execute()
+                        .data or []
+                    )
+                    return [
+                        {
+                            "neo4j_node_id": tl["id"],
+                            "label": "{} {}".format(
+                                tl.get("period_code") or "",
+                                tl.get("date") or ""
+                            ).strip(),
+                            "node_type": "TaughtLesson",
+                            "neo4j_db_name": neo4j_db_name,
+                            "is_section": False,
+                            "has_children": False,
+                            "section_id": "timetable",
+                        }
+                        for tl in lessons
+                    ]
+                return []
+            if section_id == "classes":
+                # Class members: students enrolled in this class
+                members = (
+                    sb.supabase.table("class_students")
+                    .select("student_id, status, enrolled_at")
+                    .eq("class_id", class_id)
+                    .order("enrolled_at")
+                    .execute()
+                    .data or []
+                )
+                if not members:
+                    return []
+                student_ids = [m["student_id"] for m in members]
+                status_map = {m["student_id"]: m["status"] for m in members}
+                profiles = (
+                    sb.supabase.table("profiles")
+                    .select("id, email, first_name, last_name, user_type")
+                    .in_("id", student_ids)
+                    .order("last_name")
+                    .execute()
+                    .data or []
+                )
+                return [
+                    {
+                        "neo4j_node_id": p["id"],
+                        "label": "{} {} ({})".format(
+                            p.get("first_name") or "",
+                            p.get("last_name") or "",
+                            status_map.get(p["id"], ""),
+                        ).strip(),
+                        "node_type": "Student",
+                        "neo4j_db_name": neo4j_db_name,
+                        "is_section": False,
+                        "has_children": False,
+                        "section_id": "classes",
+                    }
+                    for p in profiles
+                ]
+        except Exception as e:
+            logger.warning(f"SubjectClass children failed: {e}")
+        return []
+
     # Section containers that need lazy loading
     if node_type == "Section":
         if section_id == "timetable" and neo4j_db_name: