#1262 Hoist unreadable for-of expressions and promote the lint rule to an error

[williamthorsen]

What

Fixes lint in the agents package: Every for…of header now names what it iterates rather than burying the expression inline.

Why

unicorn/no-unreadable-for-of-expression fired at more sites in the agents package than any other rule on that package's deferral list, and the deferral held it at warn, so fresh violations landed unnoticed alongside the backlog. Clearing the sites is what lets the rule bind, and it is a prerequisite for retiring the deferral list entirely.

Details

♻️ Refactoring

• 31 loop headers across 20 files bind their iterable expression to a named const immediately above the loop. Four expression shapes were involved: an awaited call, a nullish fallback, an awaited call with a trailing method, and a new Set(…) over a mapped array. Each hoist is mechanical: for…of evaluates its right-hand side once before the first iteration, so the binding holds exactly what the header produced.
• Each binding is named for its contents. Where the obvious plural was already taken, the hoist reaches for a precise alternative rather than a suffix — listSkillDirectories binds subdirectoryNames because names is the function's own accumulator.
• The three nullish-fallback sites sit inside an outer loop over ARTIFACT_TYPE_VALUES, and their hoists stay inside it, so each fallback is still evaluated per outer iteration.
• With the sites cleared, the rule's entry leaves packages/agents/.config/eslint/deferred-lint-rules.ts and it takes the shared preset's error severity. Ten entries remain on the list, and both consumers of the object — eslint.config.ts and .config/strict-lint.config.ts — read it as before.

🧪 Tests

• 17 of the 31 sites sit in the agents test suite, where the rewrite is confined to loop headers.

Closes #1262

[github-actions]

Dependency audit

Production dependency audit passed.