Add insert command

specs/005-add-insert-command/quickstart.md

@@ -0,0 +1,28 @@
+# Quickstart – Insert Command
+
+1. **Preview an insertion at the start of filenames.**
+   ```bash
+   renamer insert ^ "[2025] " --dry-run
+   ```
+   - Shows the prepended tag without applying changes.
+   - Useful for tagging archival folders.
+
+2. **Insert text near the end while preserving extensions.**
+   ```bash
+   renamer insert -1 "_FINAL" --path ./reports --dry-run
+   ```
+   - `-1` places the string before the last character of the stem.
+   - Combine with `--extensions` to limit to specific file types.
+
+3. **Commit changes once preview looks correct.**
+   ```bash
+   renamer insert 3 "_QA" --yes --path ./builds
+   ```
+   - `--yes` auto-confirms using the last preview.
+   - Ledger entry records the position token and inserted text.
+
+4. **Undo the most recent insert batch if needed.**
+   ```bash
+   renamer undo --path ./builds
+   ```
+   - Restores original names using ledger metadata.