[#noissue] Add startup summary log for plugin loading

[Dongnyoung]

Hello,
This PR adds a small startup summary log to help improve visibility during agent initialization.

What

Add a concise startup summary log when the Pinpoint agent starts.

The log summarizes:

• detected application type
• whether plugin contexts are loaded
• number of registered class file transformers
• number of JDBC URL parsers

Why

When running Pinpoint in development or production, it is often difficult to quickly verify
whether plugins were loaded correctly and instrumentation is active.

This startup summary provides immediate visibility into the agent's initialization state
without requiring deep log inspection or debugging.

How

• Retrieve PluginContextLoadResult from the Guice injector
• Log a safe summary at INFO level during agent startup
• Wrap the logic with exception handling to avoid impacting startup stability

Scope

• Logging only (no behavior or API changes)
• Backward compatible

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud