`npm run update-frameworks` should print a diff summary

[PythonLuvr]

The update-frameworks script (scripts/update-frameworks.mjs) silently pulls fresh framework markdown from upstream. Right now you have no way to know what changed without diffing manually.

Add to the end of the script: after the update finishes, print a per-file summary of lines added / lines removed (or "no changes") for each framework file under presets/frameworks/. Something like:

Updated frameworks:
  openwar.md     +12 / -3   (commit abc1234..def5678)
  plain.md       no changes
  debate.md      +0 / -45

Use git diff --numstat against the pre-update state.