pattern-engineer-coding-standardlisted

# pattern-engineer-coding-standard ## When to activate Activate when writing, editing, refactoring, or reviewing any source file or test in any language. Skip for pure formatting, comment-only edits, or conceptual questions. ## Project memory overlay After loading this skill, also check `$MAIN_ROOT/.claude/memory/patterns/pattern-engineer-coding-standard.md` in the consuming project (resolve `MAIN_ROOT="$(dirname "$(git rev-parse --path-format=absolute --git-common-dir)")"`). If present, load it as an **additive overlay** to the rules below; if absent, skip silently. See `memory-convention` for the full contract (additivity, severity floor, conflict surfacing). ## Patterns ### Contract is iron (non-negotiable) Published contracts decide shape; this skill (and language-specific patterns) decide how to express it. Code conforms to the contract, never the reverse. The **contract** = whichever of these apply to the change: - The task issue's `Done criteria` (acceptance) and `Scenarios` (behavior) — the unit-of-work spec. - `docs/api-contract/<entity>.yaml` for any API resource touched — path (including trailing-slash spelling), HTTP verb, request body schema, response body schema, status codes per outcome, error envelope shape + `code` values, `Idempotency-Key` policy, rate-limit budget, versioning notes. - `docs/data-model/<entity>.yaml` for any persistence entity touched — table / collection names, column types, constraints, indexes. - `docs/architecture-decision-recor