fix(hive): map not-null metadata correctly

[HandSonic]

Related issue

N/A - no matching issue was found.

Summary

Hive DESCRIBE FORMATTED parsing mapped entries from # Not Null Constraints to nullable value 1. JDBC and the shared metadata model use 0 for no-nulls and 1 for nullable, so NOT NULL columns were reported backwards. This change maps those constraints to 0 and leaves other column attributes unchanged.

Affected surfaces

• Frontend / Web
• Backend / API / Storage
• Database plugin / Driver
• JCEF / Desktop packaging
• CI / Build / Release
• Documentation only

Verification

• Commands and results:
  • Red test returned nullable=1 for a NOT NULL column.
  • Focused Hive metadata test: 1 passed.
  • Hive module tests after rebase: 37 passed.
  • Plugin reactor package: succeeded.
  • Fork code and CodeQL checks: rerunning for the rebased head.
• Manual verification: N/A - strict ResultSet proxies reproduce the real formatted metadata sections.
• UI evidence: N/A

Risk and compatibility

• Public API or stored data: No API or stored data changes.
• Database or driver compatibility: Corrects Hive NOT NULL metadata to the existing JDBC convention.
• Network, privacy, or security: N/A.
• Community / Local / Pro boundary: Shared Community Hive plugin.
• Backward compatibility: Columns without a NOT NULL constraint retain existing nullable metadata.

Reviewer map

• Start here: the NOT NULL branch in HiveMetaData.columns and HiveNotNullMetadataTest.
• Failure condition: constrained columns report nullable=1 or unrelated metadata parsing changes.
• Rollback or disable path: Revert commit f0843e258cecfdfc527430de2e15034d11320425; no migration is required.

Contributor declaration

• I linked the Issue that defines this change.
• I tested the affected behavior and reported the actual results above.
• I did not include credentials, private data, or generated build output.
• I disclosed substantial AI assistance below, or this PR contains no substantial AI-generated code.

AI assistance: OpenAI Codex assisted with diagnosis, implementation, automated tests, verification, and adversarial review.