[swara030]

Description

Fixes #1941. Row detail Copy JSON could convert unmasked numbers and NULL values to strings whenever masking was active.

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• Test addition or update

Related Issue

Fixes #1941

Changes Made

• Preserve JSON types for unmasked fields while masking configured sensitive values.
• Keep binary values as hexadecimal and preserve the existing vector copy behavior.
• Add regression tests for types, masking, binary data, and excluded fields.

Testing

• I have tested this locally
• I have added/updated tests
• All existing tests pass

Test Environment

• LibreDB Studio Version: Local branch based on 1.0.0
• Browser: Not applicable (component tests)
• OS: Windows
• Node.js/Bun Version: Bun 1.4.4
• Database Type: Not applicable

Checklist

• My code follows the project's code style guidelines
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have updated the documentation accordingly
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• The required CI test job passes the 100% line-coverage gate (bun run test:coverage and bun run coverage:check)
• If I changed src/lib/db/providers/, I updated the matching docs/providers/ documentation and tests/integration/db/ tests in the same PR (provider triad)
• If the type-id has a non-null AGENT_STATEMENT_LANGUAGE row, I kept its agent leg in step: the engine overlay under src/lib/agent/languages/<statement-language>/engines/, the Agent language pack subsection of its provider document, and tests/unit/lib/agent/engine-docs.test.ts
• Any dependent changes have been merged and published

Additional Notes

The focused and component test suites, formatting, changed-file lint, typecheck, and production build passed. Full-repository lint did not complete in this environment, and the coverage gate was not run.