fix(types): allow round-trip of export → create (closes #34)

[rarce]

Summary

• parseSchema now detects DocumentType payloads ({id, codeType, jsonSchema, ...}) and unwraps the inner jsonSchema, so types export → types create works without piping through jq. Raw JSON Schema input keeps the previous behavior.
• Added an example to types create --help showing the round-trip flow.
• Cleaned up the conversionMode cast in types create and added a comment explaining why it stays: docutray@0.1.3 does not yet declare conversionMode on DocumentType. Worth filing a follow-up in docutray-node to add it; once that ships the cast can go.

Closes #34.

Acceptance criteria

• parseSchema detects {jsonSchema: {...}, ...} payloads and extracts jsonSchema.
• If jsonSchema is absent, original behavior is preserved.
• Test verifies the round-trip with a full DocumentType payload (file + inline).
• Test verifies a raw schema ({type: 'object', ...}) still parses unchanged.
• types create --help example shows the export → create flow.
• conversionMode cast documented; SDK follow-up flagged.

Test plan

• npm run build
• npm run test — 166 tests pass (10 new in test/parse-schema.test.ts)
• Manual smoke: docutray types export <code> -o /tmp/t.json && docutray types create --name "X" --code x_copy --description "..." --schema /tmp/t.json

🤖 Generated with Claude Code

[rarce]

Self-review

Findings

• Low: acceptance criterion in #34 asked for a follow-up issue in docutray-node to add conversionMode to the DocumentType type. Comment in code explains the cast but the follow-up issue is not linked. Worth opening before/after merge.

Validation

• Tests: 166 passing (10 new in test/parse-schema.test.ts), CI matrix Node 20/22 ✅
• Build: npm run build clean, package-verification ✅
• Mergeability: MERGEABLE / CLEAN

Recommendation: Ready to merge. The round-trip heuristic is correct, raw-schema path preserved, edge cases covered (jsonSchema null / non-object / array).

[rarce]

Follow-up para el cast filed: docutray/docutray-node#21. Una vez mergeado allá, el cast en src/commands/types/create.ts se puede eliminar.

[rarce]

Bumped docutray to ^0.1.4 (commit 980dbc7) — SDK now exposes conversionMode on DocumentType (docutray-node#22). Removed the unknown cast in types create and switched both create and update to use the exported ConversionMode type alias. All 166 tests still pass.

This closes the last open acceptance criterion of #34 ("limpiar el cast usando acceso directo si SDK lo expone").