Close F28 and record F31, the reason every rotation failed

Runtime death is live-proven distinct from worker deployment: no renewal in the
20:45 window, expiry and requeue at 20:55:50.

F31 explains run 4 and the F28 disposable task both dying at rotation. The
handoff action is two agent-written lines joined by the code, held to one
line's budget, and the error named a branch the answer cannot reach.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011xsXyr5J1RACo71YeKG3Pu

BURNIN.md

@@ -1187,12 +1187,11 @@ failed send, which is the correct branch.
 
 Not proven: the receipt itself, because F28 had already destroyed the pane.
 
-## F28 proof and two defects it uncovered, 2026-08-28
+## F28 closed, and three defects it uncovered, 2026-08-28
 
-The unit split is installed on workpc. F28's worker-restart direction is
-proven live. The runtime-death direction is in progress at the time of
-writing, and its result is appended below. Two new defects, F29 and F30, were found while setting the proof
-up. Neither was visible in tests.
+The unit split is installed on workpc and F28 is proven live in both
+directions. Three new defects, F29, F30 and F31, were found while setting
+the proof up. None was visible in tests.
 
 ### The tmux unit, as installed
 
@@ -1313,9 +1312,10 @@ F24  open correctness, dormant on current topology
 F25  fixed, live-proven
 F26  fixed, live-proven
 F27  fixed, live-proven
-F28  worker-restart direction live-proven; runtime-death direction pending
+F28  CLOSED, live-proven in both directions
 F29  fixed in efd0a5e, needs a coordinator rebuild
 F30  fixed in 2dc90bd, needs a worker rebuild
+F31  fixed in 6523002, needs a worker rebuild, BLOCKS every rotation
 ```
 
 ### Deployment state
@@ -1324,3 +1324,47 @@ Both fixes are committed and unbuilt. The running coordinator and worker are
 still `fbaaf79`. Run 5 should start from a deployment carrying `efd0a5e` and
 `2dc90bd`, or it will hit F30 again the first time a handoff artifact is
 rejected.
+
+### F28 runtime-death direction, live
+
+`systemctl stop orchestra-tmux` at 00:39, restarted at 00:39:37 as MainPID
+`3073848`. Every pane died with the old server.
+
+```text
+20:45:07Z  renewal window opens, no TaskLeaseRenewed appended   F16 refused
+20:55:07Z  lease deadline
+20:55:50Z  state queued v8, lifecycle reclaimed, failure_class lease_expired
+```
+
+Runtime death is now distinct from worker deployment. F16's missing-pane branch
+fires on real execution loss, which is what it was written for.
+
+The same window reproduced F30 a second time, on the deployed `fbaaf79` worker
+that lacks `2dc90bd`: session still pinned, release transaction stuck at
+`prepared`, same rejected handoff artifact.
+
+### F31: every rotation failed on a length check that named the wrong cause
+
+Two different tasks, two different agents, one error:
+
+```
+adapter: invalid handoff answer: invalid handoff authored field: prose smuggled into list
+```
+
+`parseHandoffAnswer` builds `Action` by joining the agent's `NEXT` and `WHY`
+answers with `" — "`. `Validate` then held that join to `maxAuthoredLine`, 200
+characters. The prompt asks for a sentence each and names no budget, so two
+ordinary sentences do not fit.
+
+The message named a branch the answer cannot reach. `parseHandoffAnswer` splits
+on newlines and trims every field, so no authored field ever contains `"\n#"`.
+Length was the only reachable cause, and the agent was never told what to
+shorten. It could not self-correct, so the same text failed on every retry.
+
+This is why run 4 and the F28 disposable task both died at rotation, and why
+each left the stuck transaction behind that pinned the worker slot.
+
+Fixed in `6523002`: `Action` carries the budget of both lines, the error names
+the actual length and limit, and the prompt states the limit.
+
+F31 blocks run 5 outright. Run 5's chain is four rotations.