feat: register Ripple in community catalog (#2272)

* feat: add Ripple extension to community catalog

- Extension ID: ripple
- Version: 1.0.0
- Author: chordpli
- 3 commands (scan, resolve, check), 1 hook (after_implement)
- Delta-anchored side effect detection across 9 domain-agnostic categories

* fix: move ripple entry to correct alphabetical position

Moved ripple catalog entry from between reconcile/refine to between
review/security-review. Updated README table order to match.

* fix: correct ripple alphabetical position (review → ripple → scope)

* fix: align ripple entry timestamps with catalog top-level updated_at