NOJIRA: Stabilize ORSP and add community source registry

[miloquinn]

Summary

• stabilize the ORSP 1.0 compatibility contract and machine-readable schemas
• strengthen the Dart reference source with pagination, validation, caching, and standard errors
• add contract and end-to-end conformance tests
• add governance, ecosystem, security, and multilingual documentation updates
• introduce a PR-based community source registry with safe network validation
• add static CI, trusted PR source checks, and scheduled registry health reports

Validation

• ORSP contract validation passed
• OpenAPI validation passed
• Registry static validation passed
• Generated registry is up to date
• Registry security tests passed (7/7)
• Dart analysis passed
• ORSP end-to-end conformance checks passed (42/42)
• Workflow YAML validation passed
• git diff --check passed

Safety

Registry PR network checks use the validator from the trusted base revision, do not execute submitted code, do not persist checkout credentials, reject non-public IP targets, pin TLS connections to validated addresses, and revalidate every redirect.