evolve-mq-spec

name	evolve-mq-spec
description	Design, review, or revise mq syntax and semantics in SPEC.md. Use when deciding Markdown tree behavior, selectors, query expressions, edits, schemas, diagnostics, CLI behavior, compatibility, or implementation sequencing before or alongside code changes.

Evolve the mq specification

1. Start from user-visible examples and failure cases.
2. Check the proposal against the lossless round-trip, source-local edit, deterministic selection, and library/CLI parity invariants in SPEC.md.
3. Prefer one orthogonal primitive over multiple special cases.
4. Specify syntax, semantics, diagnostics, and edge cases together.
5. Mark deferred behavior explicitly; do not leave normative behavior ambiguous.
6. Update conformance examples, affected todo/ files, and TODO.md ordering when a decision changes delivery.

Preserve the distinction between the concrete syntax tree and the derived section tree. Treat heading-derived hierarchy as a view over source Markdown, not as permission to normalize unrelated text.