[kieronlanning]

What this adds

The known-types branch, merged onto current main (the branch predates the org-harvest work, so the merge was resolved rather than fast-forwarded).

• Three new pages: Well-Known Identifiers, GUID Key Strategy and EF Core Integration. Each follows the four-section shape and says plainly what it does not enforce.
• A runnable sample at samples/Acme.Persistence: UUIDv5 derived identifiers with an idempotent, mismatch-guarded bootstrap; a sequential-GUID strategy carried as context-options data and applied by a model-finalising convention; the EF Core context, options extension, model cache key and composition. just samples runs it and fails loudly on any untrue check. It sits outside src/ so the reference implementation stays in-memory.
• Skill and template updates: purview-persistence gains EF Core integration, well-known identifiers and provider detail plus two new references; purview-engineering-principles names the conditional persistence rules; templates/AGENTS.md gains a persistence section to delete when a repository does not store data.
• Wiring: AGENTS.md, README.md, the Home table and _Sidebar.md all list the new pages and just samples.

Why it has benefit

The playbook already told repositories to choose a GUID strategy and to use EF Core as the boundary, but it stated neither rule and had no evidence. This makes the persistence guidance concrete, provider-correct (SQL Server and PostgreSQL order GUIDs differently) and demonstrated by code that runs.

Merge resolution

Conflicts were resolved in favour of the newer side so nothing from the harvest work is lost:

• docs/wiki/Home.md: keeps the current purview-dev.github.io citation and the Cross-Repository Harvest link; the branch's widened provenance sentence is kept alongside them. The stale purview-dev/purview-dev name (a redirect) is not reintroduced.
• docs/wiki/Verification-Model.md: keeps the A gate is not bypassed section and adds the sample as a deliberate fourth tier, checked by just samples and listed as Review, not as a pipeline test.
• AGENTS.md: keeps just org-inventory and just org-inventory-write, and adds just samples.
• docs/wiki/Agent-Guidance-Skills.md and AGENTS.md: keep the purview-org-harvest row and take the branch's improved purview-persistence wording.
• skills/purview-persistence/SKILL.md: keeps repository: purview-dev/engineering-playbook and takes version 1.2.

docs/wiki/Worked-Examples.md quoted a stale test summary; it now shows the numbers the merged tree actually produces (90 total, 85 succeeded, 5 skipped).

Verification

All run on the merged tree:

Check	Command	Result
Build, warning-free	dotnet build src/EngineeringPlaybook.slnx -c Debug	0 warnings, 0 errors
Lint	dotnet csharpier check .	57 files checked, clean
Tests	dotnet test --solution src/EngineeringPlaybook.slnx --treenode-filter=/*/*/*/*/	90 total, 85 passed, 5 skipped, 0 failed
CI pipeline	just pipeline-pr	Passed (restore, lint, build, tests)
Sample, SQL Server strategy	just samples	All checks passed, exit 0
Sample, PostgreSQL strategy	just samples --provider postgresql	All checks passed, exit 0
Sample, UUIDv7 fallback	just samples --provider uuidv7	All checks passed, exit 0
Migration constants	just samples --print-constants	Exit 0

The 23 Repository.UnitTests cover navigation, fence languages, the organisation snapshot (including the renamed-repository check that the Home citation passes) and skill conformance.