test(output-prompt-conformance): deep nested request-VO + depth-guard fallback cross-port

[dmealing]

Summary

Phase 4 (deep nested prompt VO conformance): gate the FR-010 output-format prompt fragment for large, deeply-nested request payloads. The existing corpus only had a 3-level pure-singular case (json-deep-nest) and shallow arrays — nothing exercised a realistic deep VO that mixes nested objects + arrays + singular, and nothing pinned the renderer's depth guard.

New cases

json-deep-mixed (roundTrip: true) — a realistic 4-level request VO mixing every nesting shape in one spec:

• singular nested objects 4 deep: payload.author.contact.{email, verified}
• an array of objects: payload.sections[] (heading + priority)
• a nested enum (LOW | HIGH) and a boolean (verified)
• an optional field carrying an example (payload.summary)

Gates guide dotted-path recursion at depth (payload.author.contact.email, payload.sections[].priority), four-level indentation, unquoted-boolean / enum rendering, and — via roundTrip — that extract(exampleOnly) reads the whole graph back with no MALFORMED/LOST_*.

json-depth-guard-fallback (roundTrip: false) — a 9-level chain that drives the renderer past MAX_NEST_DEPTH (8). At depth 8 the guard emits the flat {n9} placeholder instead of recursing into n9's child — pinning that the renderer never recurses unboundedly, byte-identically across ports (all share MAX_NEST_DEPTH = 8).

Verification

Goldens were snapshot-generated by the renderer, reviewed for correctness, then gated. Byte-identical across all five ports:

Port	Result
TypeScript	14 ✓
Python	15 ✓
C#	15 ✓
Java	14 ✓
Kotlin	✓ (BUILD SUCCESS)

The EXPECTED_CASE_COUNT guard bumps 12 → 14 in all five runners.

🤖 Generated with Claude Code