New community skills: content-hash-cache-pattern, cost-aware-llm-pipeline,
regex-vs-llm-structured-text, swift-actor-persistence, swift-protocol-di-testing
The PreToolUse Write hook blocks creation of .md files to prevent
unnecessary documentation sprawl. However, it also blocks Claude Code's
built-in plan mode from writing plan files to .claude/plans/*.md,
causing "BLOCKED: Unnecessary documentation file creation" errors
every time a plan is created or updated.
Add .claude/plans/ path to the whitelist so plan files are not blocked.