feat: JPA entity relationship rules not loaded for non-Spring JPA projects (EclipseLink/pure JPA)

[SunnyWenwen]

What problem are you trying to solve?

When running understand on a Java EE project that uses JPA with EclipseLink (not Spring), the @entity relationship extraction rules (@onetomany, @manytoone, @OnetoOne, @manytomany → depends_on edges) are never loaded because:

1. The rules are defined exclusively in frameworks/spring.md
2. spring.md is only triggered when the detected framework list includes spring
3. Projects using JPA without Spring (e.g., EclipseLink, pure JPA in Java EE/EJB) detect as ['EclipseLink', 'JPA', ...] — no spring → rules never fire
4. The resulting knowledge-graph has zero depends_on edges, making downstream ERD generation produce isolated tables with no relationships

Proposed solution (optional)

1. Decouple JPA relationship rules from Spring: Move @entity relationship extraction rules to a separate frameworks/jpa.md (or frameworks/eclipselink.md) that triggers when framework detection finds JPA, EclipseLink, or Hibernate — independent of Spring.
2. Alternatively, expand framework mapping: In project-scanner, when JPA or EclipseLink is detected, also load spring.md addendum (since the JPA rules there are framework-agnostic and apply to any JPA implementation).
3. Preferred approach: Option 1 is cleaner — the rules themselves are pure JPA spec (javax.persistence.* / jakarta.persistence.*) and have no Spring dependency.

Alternatives you've considered

No response

Which part of the project?

skill