cf-checkpointlisted

# $cf-checkpoint Save a checkpoint of this conversation's context. Optional argument: **$ARGUMENTS** (`[additional-prompt]`). ## Purpose Capture the current conversation's context up to now — goal, current state, key decisions, breaking changes, and next steps — into one concise, resumable markdown file. - Unlike `/compact`: `/compact` condenses context to keep working in the **same** conversation. `$cf-checkpoint` writes an external file meant to seed a **different**, later conversation (e.g. `$cf-checkpoint-from` in a fresh session). - Unlike `$cf-remember`: `$cf-remember` extracts durable, project-wide facts/conventions/decisions into `docs/memory/` for long-term AI recall across all future work. `$cf-checkpoint` is a transient, single-conversation resume snapshot — it captures "where we left off," not general project knowledge. **IMPORTANT — path resolution:** - Use `MAIN_REPO_ROOT` from the SessionStart bootstrap context (injected via session-init.sh). If absent, fall back to running `pwd` for `$CWD` and use `$CWD` as `MAIN_REPO_ROOT`. - Read config from `CF_CONFIG_FILE` (= `$MAIN_REPO_ROOT/.coding-friend/config.json`) — do NOT search sub-folders. - Use `CF_DOCS_ROOT` as the docs base dir (= `$MAIN_REPO_ROOT/{docsDir}` where `docsDir` comes from config, default `docs`). - Checkpoint directory: `{CF_DOCS_ROOT}/context/checkpoints/` — create it if missing. - Always resolve `file_path` as an **absolute path**. Never use relative paths — they may resolve incorrectly wh