docs: take two leaks off the public wiki, and say where the files come from

An ACCEPTED ADR ended with a stray tool-call fragment - it said nothing to a
reader and everything about how the document was produced, which is not what a
decision record is for. And the cutover playbook carried a real internal IP in a
file otherwise correctly scrubbed to documentation ranges. Both were published.

The publishability gate now catches all three shapes, so the next one fails a
build instead of reaching the wiki.

The adoption guide also told a site to copy two files that ship from nowhere:
the asset reporter and EventSaver are both on the reference site's imaging
share, not in this repository, and the guide never said so - it could not be
followed as written. It now states, per artifact, where each comes from, which
of them are pending a move into this repository, and that EventSaver can be
rebuilt from its one source file rather than taken on trust as a binary.

docs/adr/ADR-010-frontend-plugin-hooks.md

@@ -316,5 +316,3 @@ sites.
 - docs/CONTRACT-STABILITY.md (the expected-churn line this ADR answers)
 - shopdb/plugins/base.py (existing declarative hooks this pattern extends)
 - shopdb/core/api/dashboard.py, shopdb/core/api/reports.py (consumer precedent)
-</content>
-</invoke>