docs: add domain example datasets

[frydj]

Summary

Adds 5 domain-focused example datasets to Examples > Domain Examples:

E-Commerce Catalog

• Product categories, brands, products, reviews
• Demonstrates hierarchical data and relationships

Org Chart

• Departments, employees, projects, skills
• Demonstrates organizational modeling and reasoning

Knowledge Base

• Articles with tags and cross-references
• Demonstrates content management patterns

Healthcare Records

• Patients, providers, records with policies
• Demonstrates HIPAA-style access control

Supply Chain

• Suppliers, products, shipments with history
• Demonstrates time-travel and audit trails

Each includes seed data JSON files and tutorial guides.

Also updated

• examples/home.md: New examples landing page
• academic-credentials/: Minor fixes

Test plan

• Load seed data into test instance
• Verify example queries work correctly

[frydj]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• docs: add feature showcase examples #71
• docs: add domain example datasets #70 👈 (View in Graphite)
• docs: add feature reference docs #69
• docs: reorganize cookbook #68
• docs: restructure querying reference #67
• docs: restructure HTTP API reference #66
• docs: add advanced topics #65
• docs: add security guides #64
• docs: add modeling guides #63
• docs: add working with data guides #62
• docs: reorganize learn foundations #61
• docs: add getting started guides #60
• docs: add project config & infrastructure #59
• main

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