skills(automation): delete the planned-eval stub and drop its ceiling row

#14296 item 2 = A (comment 5507419465): the planned-eval stubs are
deleted and their ceilings step down; real fixtures stay. This is
round 2 of #14308 — round 1 (PR #14467, merged) implemented every
finding in skills/objectstack-automation/SKILL.md and deferred
AUTO-B-04, the evals/README.md planned-structure stub, to this ruling.

Deletes skills/objectstack-automation/evals/README.md (414 tokens —
the template listing planned eval files that do not exist) and drops
its one ceiling row from scripts/check-skills-token-ratchet.mjs. The
real fixture evals/approvals/test-revise-loop.md and its ratchet row
are untouched.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LraLgQVGq8egUwfYZpbYt1

Author: claude

scripts/check-skills-token-ratchet.mjs

@@ -431,7 +431,6 @@ export const CEILINGS = new Map([
   ['skills/objectstack-query/rules/pagination.md', 1382],
 
   // objectstack-automation
-  ['skills/objectstack-automation/evals/README.md', 414],
   ['skills/objectstack-automation/evals/approvals/test-revise-loop.md', 1329],
 
   // objectstack-ui — the two authored eval files; its `references/react-blocks.md`