feat(feature): read ERRORS.md in Phase 0 before coding (#3604)

Adds a bullet in Phase 0 step 1 to read ERRORS.md for known bugs and
non-obvious pitfalls before starting implementation. Closes #3594.

Author: PierreBrisorgueil

.claude/skills/feature/SKILL.md

@@ -16,6 +16,7 @@ description: >
 
 ### 1. Identify target module
 
+- Read `ERRORS.md` for known bugs and non-obvious pitfalls to avoid before coding.
 - Which module? Default to **ONE** unless justified.
 - **If the module doesn't exist** → run `/create-module` to scaffold it first, then continue.