Exact-size ceilings turned every two-word wording fix into a gate
event. The policy amends to: a ceiling sits at least 5% above the
doc's current size (pre-rewrite) and keeps that margin when ratcheted
to target — routine edits pass, real growth still trips the gate.
Amended together in all four policy homes (docs/AGENTS.md § Budgets,
the doc-tiers RFC, the gate script's module comment, the skill's
ratchet rule) plus the manifest values, so prose and mechanics stay
consistent.