test(node): add callgraph parity suite

[matiasdaloia]

Parent: #51

Depends on

• feat(node): add parser foundation #66
• feat(node): populate parser return sources #81
• feat(node): wire contract resolver and KB plumbing #82
• feat(node): add noble hashes contracts #83

Working unit

Add the Node parser/inference parity test suite after parser and resolver slices land.

Scope

• Cover import/require parsing, call-node fields, return-source inference, resolver-backed inferred types, and graceful degradation.
• Use JS and TS fixtures where both are supported.

Out of scope

• No new parser features unless required to fix a failing parity assertion.
• No library contract expansion.

Acceptance criteria

• Node parser, return sources, resolver/plumbing, and at least one Node contract slice are merged.
• go test ./internal/callgraph/... passes.

[matiasdaloia]

This was generated by AI during triage.

Blocker graph changed: #66, #81, and #82 are complete. #83 remains open on its contract/rules ordering decision, so this parity ticket stays agent-ready plus agent-blocked.