fix: improve error handling and logging in summary and transcript processing

- Enhanced error handling in summary generation by using fallback messages for missing assistant messages.
- Updated the `buildSummaryPrompt` function to streamline the retrieval of the last assistant message.
- Improved the `extractLastMessage` function to log errors when transcript files are missing or empty, and to ensure proper handling of messages without content.
- Added checks to ensure that messages of the specified role are found in the transcript, with appropriate logging for missing messages.
- Refactored the logging mechanism to provide clearer insights into processing failures and successes.

plugin/package.json

@@ -0,0 +1,12 @@
+{
+  "name": "claude-mem-plugin",
+  "version": "7.2.1",
+  "private": true,
+  "description": "Runtime dependencies for claude-mem bundled hooks",
+  "type": "module",
+  "dependencies": {},
+  "engines": {
+    "node": ">=18.0.0",
+    "bun": ">=1.0.0"
+  }
+}