test: managed fields excluded from projection are dropped on INSERT

[larsPlessing]

Repro (failing test) for cds-dbs#1576

Since @cap-js/db-service@2.9.0, managed audit fields (createdBy/createdAt/modifiedBy/modifiedAt) that are not exposed in a service projection are silently dropped from the generated INSERT and end up NULL in the database — instead of being filled by the default managed handler.

Root cause (per bisect): removal of resolveView() from SQLService.cqn2sql() in 2.9.0. In db-service/lib/cqn2sql.js, INSERT_entries() builds its column list from q.elements (the service-projection elements) and managed() walks that same map, so any managed field the projection omits is invisible to both and never injected.

What this PR adds

• sqlite/test/general/model.cds: base entity db.fooManaged : managed + restricted projection fooManagedRestricted { ID, value }.
• sqlite/test/general/managed.test.js: a test that POSTs through the restricted projection, then reads the underlying db.fooManaged row.

Expected result

The new test fails on current HEAD (it documents the bug):

expected {
  ID: 99, createdAt: null, createdBy: null,
  modifiedAt: null, modifiedBy: null, value: 'test'
} to contain subset { ID: 99, createdBy: 'anonymous', value: 'test' }

Draft — reproduction only, not a fix.