[minion] partio enable restores metadata branch from remote on fresh clones

cli/commands.mdx

@@ -32,7 +32,7 @@ partio enable [--absolute-path]
 3. Writes default `settings.json`
 4. Adds `.partio/settings.local.json` to `.gitignore`
 5. Installs Git hooks (`pre-commit`, `post-commit`, `pre-push`)
-6. Creates the `partio/checkpoints/v1` orphan branch
+6. Creates the `partio/checkpoints/v1` branch — if a remote tracking branch already exists (e.g., on a fresh clone), the local branch is created from the remote to preserve existing checkpoint history; otherwise a new orphan branch is created
 
 **`--absolute-path`:**
 
@@ -53,6 +53,16 @@ partio enabled successfully!
   - Ready to capture AI sessions on commit
 ```
 
+On a fresh clone where checkpoint history already exists on the remote:
+
+```
+partio enabled successfully!
+  - Created .partio/ config directory
+  - Installed git hooks (pre-commit, post-commit, pre-push)
+  - Restored checkpoint history from remote branch
+  - Ready to capture AI sessions on commit
+```
+
 If already enabled:
 
 ```

quickstart.mdx

@@ -55,6 +55,16 @@ partio enabled successfully!
 
 That's it. No config files to write, no environment variables to set.
 
+If you cloned a repository where partio was already in use, the remote checkpoint branch is detected automatically and your local branch is set up to track it — no manual `git fetch` required:
+
+```
+partio enabled successfully!
+  - Created .partio/ config directory
+  - Installed git hooks (pre-commit, post-commit, pre-push)
+  - Restored checkpoint history from remote branch
+  - Ready to capture AI sessions on commit
+```
+
 ## Your first checkpoint
 
 1. Start an AI coding session (e.g., open Claude Code)