[codex] fix(history): preserve full SQL behind previews

[HanawaBanana]

Related issue

Closes #2310

Summary

Operation-log previews previously truncated the same OperationLog instances held by local storage. After a user opened the history list, fetching an entry's details returned the shortened SQL until the backend restarted.

This change copies each operation log before preparing its 200-character preview. The list response keeps its existing truncation and more=true behavior, while the stored object and subsequent detail response retain the full SQL. A focused regression test covers the list-then-detail sequence and verifies that preview and storage objects are independent.

Affected surfaces

• Frontend / Web
• Backend / API / Storage
• Database plugin / Driver
• JCEF / Desktop packaging
• CI / Build / Release
• Documentation only

Verification

• Commands and results:
  • Before the implementation change, the focused regression command reported Tests run: 1, Failures: 1, Errors: 0; the failure showed that the preview and stored log were the same instance.
  • mvn -B -f chat2db-community-server/pom.xml -pl :chat2db-community-domain-core -am -Dmaven.test.skip=false -DskipTests=false -Dtest=OpsOperationLogQueryServiceImplTest -Dsurefire.failIfNoSpecifiedTests=false -Dmaven.test.failure.ignore=false test -> Tests run: 1, Failures: 0, Errors: 0, Skipped: 0; reactor BUILD SUCCESS.
  • mvn -B -f chat2db-community-server/pom.xml -pl :chat2db-community-domain-core -am -Dmaven.test.skip=true package -> all 7 reactor modules succeeded. Tests were explicitly skipped in this packaging pass and are covered by the focused command above.
  • git diff --check -> passed.
• Manual verification: N/A; the regression test exercises the storage aliasing and list-then-detail service sequence directly.
• UI evidence: N/A

Risk and compatibility

• Public API or stored data: No API, serialization, or storage-format changes. The service now transforms response copies instead of storage-owned instances.
• Database or driver compatibility: N/A; the behavior is database-independent.
• Network, privacy, or security: N/A; no network or security behavior changes.
• Community / Local / Pro boundary: The change stays within the Community domain service and does not alter runtime edition selection.
• Backward compatibility: Existing preview length, ellipsis, more flag, ordering, and pagination metadata are preserved.

Reviewer map

• Start here: OpsOperationLogQueryServiceImpl.operationLogPreviewList; preparePreview now copies the input before truncation.
• Failure condition: Listing a SQL statement longer than 200 characters must not change the object later returned by getOperationLog.
• Rollback or disable path: Revert commit 137b2874; there is no data migration or configuration change.

Contributor declaration

• I linked the Issue that defines this change.
• I tested the affected behavior and reported the actual results above.
• I did not include credentials, private data, or generated build output.
• I disclosed substantial AI assistance below, or this PR contains no substantial AI-generated code.

AI assistance: OpenAI Codex traced the affected call path with CodeGraph, authored the focused implementation and regression test, and ran the verification commands reported above.