github: extend LLM review rules with three new categories

github: extend LLM review rules with three new categories

Tightened from real bot reviews:

- Patch regeneration: spell out which make ... refresh command
  to recommend for each patch directory class, so the bot stops
  suggesting git format-patch for quilt-managed patches.
- Backports / cherry-picks: a backport's diff should match the
  upstream commit on main verbatim; flag only deviations and
  the missing (cherry picked from commit <sha>) trailer, not
  pre-existing style issues.
- New device support: require Hardware specification, Flash
  instructions, and MAC address layout sections in the commit
  message that introduces a new device. Two reference commits
  (986ca4c887f4, a2dcbd79a446) named so the bot can sample the
  expected shape.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Link: https://github.com/openwrt/openwrt/pull/23184
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>