### What problem does this PR solve?
- OpenTelemetry integration
- Checkpoint conformance tests
- State inspector API
- Callbacks
- A series of fault injection tests
- Pregel integration tests
### Type of change
- [x] Refactoring
### What problem does this PR solve?
- Tools management
- Pregel engine wrapper for better usage
- UT race
- Coding style
### Type of change
- [x] Refactoring
Refactor the Go agent port's logging so every log line — gin access,
agent canvas events, harness warnings, fatal boot errors — flows through
a single common.Logger (zap) backed by a rotated file, with structured
fields, level filtering, and configurable rotation.
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Co-authored-by: Claude <noreply@anthropic.com>
### What problem does this PR solve?
core module for agent layer built on top of graph engine #16039
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
go-version of Pregel-based BSP engine
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
