feat(test): Add PostgreSQL support and optimize database write logic

[Potterluo]

Title: Refactor Database Integration, Enhance Capture Utilities, and Update Dependencies

Description:

This PR introduces several key improvements to enhance modularity, performance, and maintainability:

1. Switched primary database backend to PostgreSQL

   • Replaced MySQL with PostgreSQL as the default database.
   • Database-related modules (e.g., Peewee) are now imported lazily—only when actual database storage is enabled—reducing unnecessary overhead in non-database usage scenarios.

2. Extended capture_utils functionality

   • Enhanced result capture logic to support multiple strategies (e.g., direct value capture, structured logging, and deferred serialization).
   • Improved flexibility for downstream consumers to handle diverse output formats.

3. Deferred ucmstore dependency in environment pre-check

   • Moved the ucmstore import inside the relevant function in the environment validation script to avoid early loading.
   • This reduces startup time and avoids import errors when ucmstore is not required.

4. Updated and completed requirements.txt

   • Added all missing runtime dependencies, including psycopg2, peewee, requests, pandas, pydantic, and transformers.
   • Ensured the dependency list accurately reflects the current codebase requirements.

These changes improve system decoupling, reduce cold-start latency, and ensure a smoother setup experience for new contributors.