Refuse newer save formats and add a gated dump of a live school.

Co-authored-by: Cursor <cursoragent@cursor.com>

docs/protocol.md

@@ -443,6 +443,57 @@ rebuilds the rest around it. Same success payload as GET timetable.
 Query: `classId`, `subject`, `day`, `period`. Drops that lock and rebuilds. Unknown lock is
 `404` `unknown-lesson`.
 
+## Dev endpoints
+
+These exist only when `HSchool:AllowSaveReload` is true (headless AppHost tests). They are never
+mapped in production by default. Same switch as `POST /api/dev/reload-schools`.
+
+### `GET /api/dev/schools/{id}/dump`
+
+Roster, live presence, live needs and the timetable as one JSON. The roster and lesson table come
+from the published snapshots; nodes and needs go through that school's mailbox — HTTP does not
+read the `World`. Unknown `{id}` is `404` `unknown-school`.
+
+```json
+{
+  "id": 1,
+  "name": "Гимназия №14",
+  "gameTime": "2012-04-03T10:20:00Z",
+  "running": true,
+  "people": [
+    {
+      "id": "f3.p1",
+      "fullName": "Иванова Ольга Михайловна",
+      "nodeId": "classroom-101",
+      "needs": { "Hunger": 0.92, "Toilet": 1, "Social": 0.8, "Sleep": 1 }
+    }
+  ],
+  "now": [
+    {
+      "classId": "c5A",
+      "subject": "Mathematics",
+      "teacherId": "f3.p1",
+      "roomId": "classroom-101",
+      "day": 1,
+      "period": 3
+    }
+  ],
+  "lessons": [
+    {
+      "classId": "c5A",
+      "subject": "Mathematics",
+      "teacherId": "f3.p1",
+      "roomId": "classroom-101",
+      "day": 1,
+      "period": 3
+    }
+  ]
+}
+```
+
+`nodeId` is null when the person is off campus. `now` is the lessons occurring at `gameTime`
+(empty on a break, night, weekend or holiday). `lessons` is the published table.
+
 ## WebSocket message ids
 
 Client-to-server ids live in `0x00–0x7F`, server-to-client ids in `0x80–0xFF`, so a misrouted