### Summary
`truncateText` in the `reduction` and `summarization` middlewares
truncates with `s[:maxLen]`, which slices by byte. When `maxLen` lands
inside a multi-byte character (common with CJK or other non-ASCII
content flowing through the agent), the string is cut mid-rune and the
tail byte(s) become invalid UTF-8. That broken text then goes into the
reduced context / summary prompt.
`TruncateToolResult` in the same `reduction` package already avoids this
by slicing on a rune boundary and even notes it in a comment. This PR
makes the two `truncateText` helpers do the same, so they stay
consistent with the existing helper.
Both functions keep their existing output shape (summarization still
appends `...`). Added a small unit test in each package covering ASCII
truncation and a CJK string, asserting the result stays valid UTF-8.
### 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.
---------
Co-authored-by: Claude <noreply@anthropic.com>
## Summary
Stabilizes the Go unit-test surface so the test suite can run reliably
in CI and locally via \`bash build.sh --test\`.
## Verification
\`\`\`bash
bash build.sh --test -- -count=10 -run TestWithCancel_SequentialAgent
./internal/harness/core/
bash build.sh --test -- -count=5 -run TestSiliconflowChatExtracts
./internal/entity/models/
bash build.sh --test # full suite
\`\`\`
All previously failing packages (\`admin\`, \`cli\`, \`handler\`,
\`parser\`,
\`router\`, \`service\`, \`service/chunk\`) now build and test
successfully.
\`TestWithCancel_SequentialAgent\` passes 10/10 (was flaky). SiliconFlow
reasoning test passes after switching the assertion to the SiliconFlow
wire
format.
---------
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)
