M5a review: tasks 01 to 22 and the device check; tips I16, I17, T34 to T40

Two review entries in the implementer log: tasks 01 to 15 (the header
forgery, review ids, the runbook entries, log rows written from memory)
and tasks 16 to 22 with the device check on straylight (the ledger
raising state by the grant's label, the note answers, the stale target/
that stalled task 21, the clippy 1.95 stop, the fake podman race). Two
short rules go into AGENTS.md: stop after one check when a test outside
the task fails, and write the log row from the diff.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

AGENTS.md

@@ -77,6 +77,10 @@ These come from defects found in review. The evidence is in `docs/implementer-le
   angle-bar turn markers), in code, comments, commands or your log. Build them from pieces
   (`concat!("<", "think")`) and name them in words: text holding them becomes your own control
   tokens when you read it.
+- When a test outside your task fails, check once whether it fails without your change, then stop
+  and report both results. Do not keep experimenting, and never add a file the task does not list,
+  not even a temporary one.
+- Write your log row from `git diff` after staging, naming only what the diff shows.
 
 ## The gate