Fix README links, add missing skills, correct invocation classification

- Fixed 3 broken links in root and common READMEs (pkm-curation,
  forge-interaction, forge-preferences were pointing to wrong buckets)
- Moved project-context-pack from model-invoked to user-invoked
  (matches its disable-model-invocation: true flag)
- Added 8 missing user-invoked and 6 missing model-invoked skills
  to root and common READMEs
- Added all 9 engineering skills to engineering README
  (was missing codebase-design, domain-modeling, resolving-merge-conflicts,
  tdd, grill-with-docs, improve-codebase-architecture, setup-skills,
  to-issues, to-prd, triage)
- Added pkm-curation to pkm README
- Updated personal README to note both skills moved elsewhere
- Added all forge skills to deprecated README
- Added .gitignore for docs/adr/
- Added docs/agents/ reference files
- Added project context cache

common/pkm/README.md

@@ -5,6 +5,7 @@
 - [conversation-summary](conversation-summary/SKILL.md) — Summarize the current AI conversation into a new Obsidian markdown note and matching transcript file.
 - [crit](crit/SKILL.md) — Brainstorm with AI using the CRIT framework to generate and evaluate ideas.
 - [knowledge-gardener](knowledge-gardener/SKILL.md) — Run vault-aware semantic search, synthesis, note creation, linking, and Zettelkasten workflows for this Obsidian vault.
+- [pkm-curation](pkm-curation/SKILL.md) — Curate an Obsidian-style personal knowledge vault by classifying notes, normalizing frontmatter, improving structure, extracting atomic notes, and adding meaningful wikilinks.
 - [research-vault](research-vault/SKILL.md) — Research a topic through a one-question-at-a-time learning conversation and save a linked Obsidian research packet.
 
 ## Model-invoked