feat(schema): register complete schema for pull_request entity type

[castor-agent]

Fixes #158

Registers a complete schema declaration for pull_request entity type in the bootstrap registry with canonical name fields, temporal fields, reference fields, and merge policies.

Summary

• src/services/schema_definitions.ts: Added linked_issues field (type: string) and reference_fields array declaring three typed edges — author→contact, repo→github_repo, linked_issues→issue — all using REFERS_TO. Bumped schema_version to 1.1. Existing canonical_name_fields ([{composite: ["number","repo"]}, "url"]) and temporal_fields (created_at, merged_at, closed_at) were already present and correct.
• docs/subsystems/record_types.md: Added pull_request to the Productivity Schema Family table and documented a full Pull Request subsection under §4.2 covering required fields, optional fields, identity rule, aliases, reference fields, and schema registration location.
• tests/unit/pull_request_schema.test.ts: 20 unit tests covering ENTITY_SCHEMAS registration, canonical_name_fields (composite and url fallback), temporal_fields (three entries with correct event types), reference_fields (all three entries), field declarations, merge policies, and no-dangling-reference-field constraint.
• docs/testing/automated_test_catalog.md: Regenerated to include the new test file.

Test plan

• npm run type-check passes (no type errors)
• tests/unit/pull_request_schema.test.ts passes — 20/20 tests green
• Full test suite passes (334 files, 3271 tests passed; 2 pre-existing failures unrelated to this change)
• npm run generate:test-catalog && npm run validate:test-catalog passes
• npm run lint, npm run format:check, npm run lint:site-copy all pass

🤖 Generated with Claude Code

[github-actions]

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[castor-agent]

/create_pr skill audit

Automated audit against the /create_pr skill (Neotoma plan ent_8cde942847555a83253dfe5b), which defines the standard PR description structure (Problems / Solutions / UX improvements / Documentation / Test plan / Breaking changes), the pre-PR checklist from .claude/rules/change_guardrails_rules.md, and the functional-change documentation gate (docs entry + docs/site/site_doc_manifest.yaml + docs server surfacing).

Verdict: does not fully meet standards. Gaps below; recommended changes follow each item.

Findings

• Missing required sections: Problems, Solutions, UX improvements, Documentation, Breaking changes.
• Breaking changes section MUST be present, even for non-breaking PRs (write No breaking changes.).
• PR body does not confirm the doc is reachable via the docs server (src/services/docs/) or list the specific docs/...md path under the Documentation section.

Recommended changes

Update the PR description to match the skill template exactly:

## Problems
- <Concrete pain point or gap.>

## Solutions
- <Concrete change made.>

## UX improvements
- <User-visible behavior change, or `No user-visible change.`>

## Documentation
- <docs/... path(s) added or updated; parameters/outputs/examples/error modes covered.>
- <`docs/site/site_doc_manifest.yaml` entry added/updated; docs service tests pass.>
- <Or: `No functional change; no user-facing docs required.`>

## Test plan
- [ ] `npm run type-check`
- [ ] `npm test`
- [ ] `npm test -- src/services/docs` (if docs changed)
- [ ] Manual verification: <steps>

## Breaking changes
No breaking changes.

## Related
- Plan: <Neotoma plan entity_id or docs/ path>
- Issue(s): <#N>

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Functional surfaces detected from the diff: CLI, MCP, Schema. Per the skill, the Documentation section must point at a real docs/...md path covering parameters, outputs, at least one example, and error modes, and the doc must be listed in docs/site/site_doc_manifest.yaml so it is surfaced by the docs server and docs site.

Posted by /create_pr skill audit run. See .claude/skills/create_pr/SKILL.md for the full template.