Add full-compaction hook example

packages/coding-agent/examples/hooks/README.md

@@ -25,6 +25,9 @@ Prevents session changes when there are uncommitted git changes. Blocks clear/sw
 ### auto-commit-on-exit.ts
 Automatically commits changes when the agent exits (shutdown event). Uses the last assistant message to generate a commit message.
 
+### full-compaction.ts
+Custom context compaction that summarizes the entire conversation instead of keeping recent turns. Uses the `before_compact` hook event to intercept compaction and generate a comprehensive summary using `complete()` from the AI package. Useful when you want maximum context window space at the cost of losing exact conversation history.
+
 ## Usage
 
 ```bash