fix: Improve plugin logging and add test/coverage CI

[lan17]

Summary

• replace the original debug-toggle plan with a real logLevel model supporting warn, info, and debug
• keep default warn mode quiet so normal operation only logs warnings and explicit block events
• use info for one-line lifecycle visibility such as client init, gateway warmup, and agent syncs
• keep verbose per-tool diagnostics, timing, args, and evaluation context behind debug
• keep config.debug as a deprecated compatibility alias for logLevel=debug
• document the new logging configuration in the plugin schema and README

Validation

• add TypeScript typechecking with tsc --noEmit
• add behavioral Vitest coverage for logging, plugin hooks, session context, session store, tool catalog, runtime helpers, and shared utilities
• add CI steps for lint, typecheck, tests, and coverage generation
• generate coverage/lcov.info, upload coverage artifacts in CI, and upload to Codecov when CODECOV_TOKEN is configured

Testing

• npm run lint
• npm run typecheck
• npm test
• npm run coverage

[galileo-automation]

🎉 This PR is included in version 1.3.3 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

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