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/engineering/README.md

@@ -2,9 +2,17 @@
 
 ## User-invoked
 
-_None yet._
+- [grill-with-docs](grill-with-docs/SKILL.md) — A relentless interview to sharpen a plan or design, which also creates docs (ADRs and glossary) as we go.
+- [improve-codebase-architecture](improve-codebase-architecture/SKILL.md) — Scan a codebase for deepening opportunities, present them as a visual HTML report, then grill through whichever one you pick.
+- [project-context-pack](project-context-pack/SKILL.md) — Build and refresh a bounded repo context memory file so agents use disciplined search instead of repeated browsing.
+- [setup-skills](setup-skills/SKILL.md) — Configure this repo for the engineering skills, set up its issue tracker, triage label vocabulary, and domain doc layout.
+- [to-issues](to-issues/SKILL.md) — Break a plan, spec, or PRD into independently-grabbable issues on the project issue tracker using tracer-bullet vertical slices.
+- [to-prd](to-prd/SKILL.md) — Turn the current conversation into a PRD and publish it to the project issue tracker — no interview, just synthesis of what you've already discussed.
+- [triage](triage/SKILL.md) — Move issues and external PRs through a state machine of triage roles — categorise, verify, grill if needed, and write agent-ready briefs.
 
 ## Model-invoked
 
-- [forge-interaction](forge-interaction/SKILL.md) — Work safely with GitHub and Gitea repositories, issues, pull requests, releases, and remote forge state.
-- [project-context-pack](project-context-pack/SKILL.md) — Build and refresh a bounded repo context memory file so agents use disciplined search instead of repeated browsing.
+- [codebase-design](codebase-design/SKILL.md) — Shared vocabulary for designing deep modules.
+- [domain-modeling](domain-modeling/SKILL.md) — Build and sharpen a project's domain model.
+- [resolving-merge-conflicts](resolving-merge-conflicts/SKILL.md) — Resolve an in-progress git merge/rebase conflict.
+- [tdd](tdd/SKILL.md) — Test-driven development.