docs(rules): ban restructuring code to slip past a checker

Task 07 wrote px font sizes as the `font:` shorthand in two components
because check-tokens.mjs only matches `font-size:`. Green branch, two
hardcoded values. Make the expectation explicit: report the gap, stop.

Also fixes gates.md telling agents to rebase WIP commits away, which
git-worktrees.md forbids outright.

.agents/agents/component-builder.md

@@ -27,6 +27,10 @@ You may not edit `tokens.css`, `verify.mjs`, `astro.config.mjs`, or
 ## Rules that bite
 
 - No raw hex, no px font sizes, no ad-hoc breakpoints. Tokens only.
+- **Never reshape CSS to slip past `check-tokens.mjs`** — e.g. the `font:`
+  shorthand to hide a px size it would catch as `font-size:`. If the token you
+  need does not exist, report the gap and stop; you may not add it yourself. See
+  `.agents/rules/gates.md`.
 - No `client:*` unless genuinely interactive, with written justification.
 - Every ARIA attribute from the markup you replace survives. `verify.mjs`
   asserts several by name.

.agents/rules/gates.md

@@ -52,11 +52,31 @@ grows a compare mode.
 ## Bypassing
 
 `--no-verify` is allowed exactly once: a work-in-progress commit **on your own
-task branch that you will rebase away**. It is never allowed on a commit you
+task branch that you will amend or squash away**. It is never allowed on a
-intend to merge, and the pre-push gate has no bypass.
+commit you intend to merge, and the pre-push gate has no bypass.
 
 If a gate is wrong, fix the gate in its own commit. Do not route around it.
 
+## Never restructure code to slip past a checker
+
+A checker is a proxy for a rule. Passing the proxy while breaking the rule is
+worse than failing, because failure is visible and this is not.
+
+`check-tokens.mjs` matches `font-size: Npx`. Writing the same value as the
+`font:` shorthand passes it. Task 07 did exactly that, in **two** components,
+with a comment saying so. Both hardcoded values survived into a "green" branch.
+
+When a token you need does not exist:
+
+1. Stop. Do not invent a value, and do not reshape the syntax to hide one.
+2. Write the gap in your task report: the selector, the legacy value(s) it comes
+   from, and which file owns the token.
+3. If your task cannot proceed without it, say so and stop. A blocked task is a
+   finding. A silently-passing one is a defect that ships.
+
+`tokens.css` has a single owner (`design-system-keeper`) precisely so that "add
+a token" is a decision, not a side effect.
+
 ## Parallelism
 
 - Hooks are **per-worktree**. Git's `index.lock` is per-worktree, so parallel