fixed event/live transition

docs/claude/invariants-session-and-export.md

@@ -59,6 +59,17 @@ Part of [CLAUDE.md](../../CLAUDE.md). These are rules that cost a defect to lear
   out — a source whose streamer was merely down during one run would silently vanish from the
   only list it can be picked from, for ever. Keeping the old file loses nothing: a run that
   configured nothing had nothing worth persisting.
+- **It refuses again while `replaying` is set: a file view is not the source's session.** Same
+  argument, different cause — this view configured nothing about the stream. A plain replay leaves
+  the rows where the user put them, so its save would merely be pointless; a **group** rebinds every
+  slot to its own renamed channels and the save wrote `signals = ["square (A)", …]` into the file.
+  Nothing noticed until the way back: *Go live* re-applies the session, those names match no live
+  signal, so nothing was enabled and **the live view came back with no channels at all** — on the
+  window the poisoned file carried, which is also how it swallowed the window restore below it. The
+  reading is `[events] live restored (after a group)`: the symptom was a stuck `pending=1` beside
+  `channels=0`, because the restore waits for a channel list that was never going to arrive. The
+  explicit *Save as* is deliberately **not** guarded: that one is a user's own answer to "save this
+  view", and its dialog reports the outcome.
 
 ## A configuration is a named session, and a source may hold several