Docs: update for new safety features and fix SyncMode enum names
- CLAUDE.md: document atomic writes, input size limits, path validation,
file download size cap, workspace path validation, taskStack auto-cleanup
- API.md: add Input Validation & Safety section with size limits table,
atomic writes list, and path safety documentation
- API.md: fix SyncMode enum names (PushOnly/PullOnly -> Push/Pull)
- API.md: add missing on_progress parameter to sync_workspace examples
- Update current state date to 2026-04-06
https://claude.ai/code/session_01F67yfLLmSaBtT7aKKNus1M