- ingest_file_with_config: lowercase normalize ext (caller-side) +
early error on unsupported extension (`.docx` etc. now Err with
helpful message instead of silent skipped_by_extension counter).
New test ingest_file_errors_on_unsupported_extension.
- ingest_stdin_with_config: doc comment explaining intentional
double-call of ensure helpers (idempotent + ~ms negligible).
- external::inject_frontmatter: simplify precheck via single
trim_start binding + add CR-only line ending edge case.
- external::inject_frontmatter: doc note on yaml_quote escape
contract (agent-supplied titles with special chars are safe).
Round 1 review summary: #111 (comment)
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>