feat(#2789): trim skill description anti-patterns; enforce 100-char budget (#2823)

* feat(#2789): trim skill description anti-patterns; enforce 100-char budget

- Trim descriptions in all commands/gsd/*.md files over 100 chars
- Remove flag documentation from descriptions (belongs in argument-hint)
- Remove Triggers: keyword stuffing
- Add scripts/lint-descriptions.cjs — fails on descriptions > 100 chars
- Add npm script: lint:descriptions
- Add tests/enh-2789-description-budget.test.cjs

Closes #2789

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* docs(#2789): add CHANGELOG entry for description budget lint

* docs(#2789): update COMMANDS.md descriptions; add skill description standards note

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

docs/FEATURES.md

@@ -1791,6 +1791,7 @@ Test suite that scans all agent, workflow, and command files for embedded inject
 - REQ-CTXRED-01: System MUST truncate oversized markdown artifacts to fit within context budgets
 - REQ-CTXRED-02: System MUST order prompts for cache-friendly assembly (stable prefixes first)
 - REQ-CTXRED-03: Reduction MUST preserve essential information (headings, requirements, task structure)
+- REQ-CTXRED-04: Skill `description:` fields MUST be ≤ 100 chars; enforced by `npm run lint:descriptions` (see `scripts/lint-descriptions.cjs` and `tests/enh-2789-description-budget.test.cjs`)
 
 **Process:**
 1. **Measure** — Calculate total prompt size for the workflow