feat(org): add limits db engine for org build limits

[alexhholmes-work]

Database engine for the org_build_limits table with full CRUD operations, following the existing engine pattern used by other database packages.

Changes

• Add database/limits package with Engine struct implementing the LimitInterface
• Implement CreateOrgBuildLimit, GetOrgBuildLimit, UpdateOrgBuildLimit, and DeleteOrgBuildLimit operations
• Add LimitInterface to the top-level database.Interface and wire it into database.New
• Add table creation in limits/table.go with org_build_limits schema
• Add engine options (WithClient, WithLogger, WithSkipCreation) in limits/opts.go
• Add integration tests covering all CRUD operations
• Add unit tests for all engine methods, options, and table creation