fix(dasel): update converter for v3 CLI

[cyphercodes]

Summary

• update the dasel converter to use the dasel v3 CLI (--var ... --out ...) instead of removed --file/--read/--write flags
• close the child stdin pipe after spawning dasel so the v3 process does not wait for input under Bun
• add unit coverage for the generated v3 arguments and stdin handling

Fixes #579.

Tests

• PATH=/tmp/oss-pr-pipeline/convertx-579-tools/bin:$PATH bun test tests/converters/dasel.test.ts
• real dasel v3.11.2 YAML→JSON smoke test through convert()
• bun run lint:tsc
• bun run lint:prettier
• git diff --check
• PATH=/tmp/oss-pr-pipeline/convertx-579-tools/bin:$PATH bun test

---

Summary by cubic

Switch dasel converter to v3 CLI flags (--var ... --out ... $data) and close stdin so v3 doesn't wait under Bun, fixing #579. Adds unit tests for argument generation and stdin handling.

^{Written for commit 87ef3a0. Summary will update on new commits.}

[cubic-dev-ai]

No issues found across 3 files

_{Re-trigger cubic}