Add /wiki-update skill for project-specific reference wiki ingest

[nsmiller2501]

Summary

This PR adds /wiki-update, a skill for ingesting PDFs from references/raw/ into a project-specific markdown wiki.

Depends on

• Add /read-pdf skill with cached marker-based PDF-to-markdown conversion #6 (/read-pdf) for the preferred marker-based converted-markdown ingest path.
• Add /bib-update skill for idempotent references.bib maintenance #7 (/bib-update) for post-ingest BibTeX maintenance.

What changed

• Adds the /wiki-update skill and a references/CLAUDE.md template.
• Scaffolds references/raw/, references/wiki/, references/wiki/figures/, wiki/index.md, and wiki/log.md on first run.
• Uses project context from root CLAUDE.md to relevance-filter paper content.
• Auto-selects among Protocol M (/read-pdf converted markdown), Protocol E (cached _text.md extract), and Protocol S (split-PDF fallback).
• Gates filename renames and destructive wiki edits behind user approval.
• Writes the wiki log only after wiki edits succeed, with rollback scoped to wiki pages and log entries.
• Hands bibliography maintenance to /bib-update after successful ingest.
• Adds internal and public README documentation plus an entry in the skills index.

Testing

• Reviewed the branch diff against the PR notes.
• Re-audited dependency references, rebuild behavior, rollback scope, destructive edit approval, and docs consistency.
• No automated tests were run; this is a skill/documentation protocol update.