#24 budget: skill cap 900->1000 (PLAN M2 + test) deliberate doc-truth headroom

Plan §M2 + cli.rs skill_within_budget. The pre-agreed deliberate budget decision: doc-truth wave (#25-#31) adds real contract bytes (merge reword ~+30B) and 897/900 has no room. 1000B cap, lines stay 30. Changes: tests/cli.rs assert bytes<=1000; wiki/docs/PLAN.md §M2 skill cell 900->1000; skill.md re-sync with #25 reword. Golden test (body == SKILL_TEXT) unchanged. DONE: budget test passes at 1000; PLAN cell matches; skill <=1000B.