docs(CHANGES): Note add/discover --no-merge option

why: Document the new flag so users spot the opt-out quickly.
what:
- mention the shared --no-merge switch in the improvements section

Author: tony

CHANGES

@@ -49,6 +49,8 @@ _Upcoming changes will be written here._
 - Accepts repositories by path (`vcspull add ~/study/python/project`), detects
   `origin` remotes, and prompts for confirmation. Use `--yes` to auto-approve
   scripted runs.
+- Adds `--no-merge` so both `vcspull add` and `vcspull discover` can skip
+  auto-merging duplicates while still surfacing warnings for manual follow-up.
 - CLI previews contract workspace paths to `~/…` for consistency with other
   commands and easier scanning.