Follows docs#203, which recorded the two defects Phase 13's acceptance walk found
and left them for placing. They are fixed in website#181, so Phase 13's as-built
says so and says what the fix was rather than leaving a reader to find the PR.
Two other files were describing a contract the code did not honour, which is why
the second defect could exist at all:
* BACKEND_DESIGN's `template_keys` column row said only that keys are
shape-checked. It now says the one thing that was actually load-bearing --
`digest` is a key that is NOT a channel, because it names a MODE's body --
and that the rules validator rejected it until website#181, which made every
rule shipping one unsaveable from the Rules screen, core's own included.
* MODULE_API 2.4 already told modules they may point `template_keys` at
`notify.digest` and never said what `digest` was. A module author reading it
would reasonably have expected it to be a channel. One bullet, next to the
generic-bodies one that sends them there.
No contract changed; the docs were right and the code was wrong. No
MODULE_API_VERSION bump for the same reason.
Co-Authored-By: Claude <noreply@anthropic.com>