Remove Coordination Issue References From spec/ Blocking Promotion #3843 #3844

Promotion PR #3843 has one open, valid Copilot finding, thread at spec/fidelity-model.md:14. The line references ptr727/ProjectTemplate#735. That breaks the comment-and-doc-style rule "Carried files reference no coordination machinery", under which spec/ stays repository-neutral. git grep 'ptr727/ProjectTemplate#' -- spec/ also finds one such reference in spec/divergences.json, which Copilot did not flag.

The reference was already on main. #3811 only added text to the same line.

Done when:

• Neither spec/fidelity-model.md nor spec/divergences.json references a ptr727/ProjectTemplate# issue.
• The reasoning those references support is kept.

This is a promotion fix. It blocks #3843, so it ranks first under backlog-burndown "The Promotion Boundary" step 5.