docs: fix stale Claude Code plugin description in root README

The umbrella install section still described the plugin as bundling "skills,
hooks, and an agent" — the agent was removed in the v0.4 redesign. Updated to the
current surface: hooks (briefings + checkpoints), the opt-in output style, and the
/basic-memory:* skills.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Signed-off-by: phernandez <paul@basicmachines.co>

Author: phernandez

README.md

@@ -197,7 +197,9 @@ just package-check-openclaw
 
 ### Claude Code plugin
 
-The Claude Code plugin bundles Basic Memory-aware skills, hooks, and an agent:
+The Claude Code plugin is the bridge between Claude's working memory and Basic
+Memory — session-start briefings, pre-compaction checkpoints, an opt-in capture
+output style, and `/basic-memory:setup` · `:remember` · `:share` · `:status`:
 
 ```bash
 claude plugin marketplace add basicmachines-co/basic-memory \