Add advisory test-surface cues to simplicity guidance

[geldmacher]

Summary

• Expand weak verification theater with a short Test surface subsection: four authoring questions and junk-pattern evidence cues, rewritten in the existing Evidence-Guided Simplicity voice.
• Point explicit reviews and authorized test edits at those cues from the Efficiency skill.
• Record the documentation change under Unreleased. No version bump and no new skill, command, or agent.

Scope

Guidance only. A missing authoring answer means do not add that test yet; existing tests are not removed from the pattern name alone. The cues do not authorize creating, running, or deleting tests outside an approved change, and they do not add coverage or mutation gates.

Validation

npm run check:targets, npm run validate, and npm run check:links passed. The full test suite passed when Git’s local URL rewrite was not applied to fixture remotes (100 tests). A plain npm test in this environment fails those release-script cases because git remote get-url rewrites git@github.com: to a tokenized HTTPS URL; that failure is independent of this docs change.