Movement-aware parsing core, derivation artifacts, CLI workflow, and docs refresh

[yzhouwang]

Summary

This PR upgrades the parser from baseline feature flattening to a movement-aware pipeline for a controlled English grammar, and makes outputs directly usable for linguistics experiments.

Main goals completed:

• preserve existing ambiguity regression (PP attachment = 2 parses),
• stop treating MOVED as only a plain feature shortcut in runtime behavior,
• add memoization/cycle safety for recursive search,
• expose research artifacts (PNG trees + derivation JSON),
• document capabilities, limits, and reproducibility.

What Changed

1) Movement-aware parsing semantics

• Added explicit movement-chain lifecycle tracking (introduced/discharged/pending).
• Added feature-compatibility checks for discharge behavior.
• Added unresolved-chain diagnostics to exported derivations.

2) Parser/search stability

• Added canonical parser state memoization and cycle/dead-state control.
• Preserved intended ambiguity while avoiding runaway recursion in cyclic functional rules.
• Added deterministic traversal/order behavior for stable outputs.

3) Controlled grammar support

• Expanded controlled English lexicon entries for:
  • declaratives,
  • do-support declaratives,
  • yes-no questions,
  • wh-object questions,
  • PP attachment ambiguity.

4) Research outputs

• Tree rendering now includes movement-chain markers (e.g., CH1) and optional movement arrows.
• Added derivation JSON artifact export with:
  • token stream,
  • step trace,
  • chain events,
  • well-formedness + unresolved-chain info.
• Added deterministic artifact naming per parse.

5) CLI workflow

• Added CLI options for:
  • single sentence parse,
  • batch core fixtures,
  • output format (png|json|both),
  • output directory,
  • toggling movement arrows.

6) Tests and docs

• Added/updated tests for:
  • PP ambiguity exact-count regression (2),
  • do-support / yes-no / wh coverage,
  • rejection controls for malformed/inverted/tensed-after-did cases,
  • chain invariants and termination stress behavior.
• Added capability and quality docs:
  • docs/capability_matrix.md
  • docs/quality_report.md
• Updated README to match current behavior and CLI usage.
• Improved .gitignore for Rust/macOS/generated artifacts.

Validation

• cargo test -q
  • result: 31 passed, 0 failed, 5 ignored
• cargo clippy --all-targets --all-features -q
  • result: clean

Current Scope / Known Limits

• Grammar is intentionally controlled and small (not open-domain English).
• Some question analyses still rely on a constrained normalization bridge; fully strict surface-faithful derivations for all constructions remain in progress.
• Formal claims should be interpreted over this controlled grammar and implementation scope.