Drop the pr/issue/markdown variants from `/trekplan --export`. Claude Code
reformats a plan into a PR body, issue comment, or stripped markdown ad-hoc
on request, so a dedicated export path added maintenance without value.
Keep `--export headless` as a backwards-compatible alias for `--decompose`
and relabel it as the decomposition entry it actually is.
- commands/trekplan.md: Phase 1 parse rejects non-headless formats and sets
mode = decompose for headless; delete the Export phase; rename Phase 1.6 →
Phase 1.5 (Decompose); update the mode enum, argument-hint, and usage block.
- docs/command-modes.md, README.md: export row relabeled as a --decompose alias.
- tests/commands/trekplan.test.mjs: +2 V15 pins (variants gone, headless kept).
Non-breaking (plan D-register). Tests 731 (729 pass / 2 skip / 0 fail), bar
`node --test`; `claude plugin validate` green (1 accepted warning).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LqBYc8Ltrk7LipyJmGxXiB
