Allow page lists in multi-page reference titles

[hua7450]

Summary

Lets a parameter reference title carry a page list when the reference cites several pages of one PDF. A reference that cites one page still keeps the page only in the href.

Refs PolicyEngine/policyengine-us#10008

Rule

• One reference entry per source document. URLs that differ only by #page= are the same source.
• One cited page: #page=57 in the href, no page text in the title.
• Several cited pages: the href opens the first cited page, and the title ends with #page 72-75 (consecutive) or #page 29,32-33,36,41 (nonconsecutive). The title is quoted, because an unquoted # starts a YAML comment and truncates the title.
• The href fragment is one page. Never #page=1,3,5.
• A multi-page table is not split into one entry per page.

Why

The model-development reference said "no page number in title", and the rules-engineer and implementation-validator agents said page numbers go in href:, never in title:. With one entry per source, a reference citing pages 72-75 could show only page 72. PolicyEngine/policyengine-us#9743 uses the page-list title, and its round 3 review pointed out that the skill guidance contradicts it; the implementation-validator would also report that title as CRITICAL.

Changes

• skills/policyengine-model-development/references/parameters.md: example comment and the reference bullet.
• targets/claude/agents/country-models/rules-engineer.md: reference-format section, correct and forbidden examples, title and href rules, and the self-check.
• targets/claude/agents/country-models/implementation-validator.md: the reference-format check, and the example finding now names a one-page reference.

Not included

• Version bump, left to the release PR.
• Item 5 of Document the reference page-citation convention in AGENTS.md policyengine-us#10008 (a distinct table section starting on a page the href does not open gets its own entry).
• The policyengine-us AGENTS.md change, which that issue tracks.

Test plan

• CI passes

🤖 Generated with Claude Code