fix(nlab-api): broaden enum provenance analysis

[JacobZyy]

Response fields populated through name(), helper methods, constructors, builders, or object copies could lose their enum association. Known defaults such as 99 could also disappear from the generated enum, incorrectly narrowing its value set.

Trace typed assignments and finite value propagation, share enum projections across response, request, and reverse lookup analysis, and retain extra literal members in field-specific enum variants. Preserve container shapes and report missing source or dynamic transformations without inventing values. CodeGraph itself is unchanged.

Validation: cargo fmt --check, cargo clippy --locked --all-targets --all-features -- -D warnings, and all 399 repository tests passed. Ten coverage groups also passed with fresh real CodeGraph indexes; the original 18 probes verify actual generated enum members, with negative cases for unsafe narrowing and unrelated types.