fix(metadata): prevent table page offset overflow

[HandSonic]

Related issue

N/A - no matching issue was found.

Summary

Cached relational table pagination calculated (pageNo - 1) * pageSize with int arithmetic. Accepted maximum-bound requests wrapped to negative indexes and reached subList, raising IndexOutOfBoundsException. This change derives the offset and end with long, returns an empty out-of-range page, and only converts indexes after proving they fit the table list.

Affected surfaces

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

Verification

• Current-main reproduction: original test suite ran 3 tests; maximum pageNo / pageSize produced IndexOutOfBoundsException: fromIndex = -200000 before the fix.
• After main integration, owning reactor tests and package passed: domain-core 304, SPI 147, tools 77, domain-api 27; 555 total, zero failures/errors/skips.
• Command: mvn -B -ntp -f chat2db-community-server/pom.xml -pl :chat2db-community-domain-core -am -Dmaven.test.skip=false -DskipTests=false '-Dsurefire.includes=**/*Test.java' -Dsurefire.failIfNoSpecifiedTests=false -Dmaven.test.failure.ignore=false package. Test JVM home/temp were isolated.
• Executable backend package passed. Playwright CLI created an actual SQLite connection through the UI and verified eight real API cases: normal pages, ordinary out-of-range pages, two overflow boundaries, search totals, search plus overflow, empty search results, then reload.
• The two integrated PR files are byte-identical to the Web-tested version. Current-head CI is available in PR checks.
• Extreme page numbers were sent as browser HTTP requests; this is not claimed as a normally reachable UI pagination action.

Risk and compatibility

• Public API or stored data: No API or storage format changes.
• Database or driver compatibility: Applies only to local cached table list slicing; metadata retrieval is unchanged.
• Network, privacy, or security: N/A.
• Community / Local / Pro boundary: Shared Community metadata service.
• Backward compatibility: Normal pages preserve their existing ordering, totals, and contents; out-of-range pages remain empty.

Reviewer map

• Start here: DbTableServiceImpl.pageQuery and the maximum-bound case in DbMetadataAccessPolicyTest.
• Failure condition: an accepted page request produces a negative list index, or normal page slicing changes.
• Rollback or disable path: Revert commit 785fe519d8cf776ed9c3d47f0d55e19e59b60c5e; no migration is required.

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 assisted with diagnosis, implementation, deterministic tests, verification, and adversarial review.