feat: paginate Studio user management

[tju-yxq]

Summary

• add server-side pagination to GET /api/studio-users with default page=1, pageSize=20, and a 100-row maximum
• filter by username substring, administrator role, and enabled status
• keep stable username ASC, id ASC ordering and perform filtering/pagination in MyBatis-Plus
• reject invalid pagination and oversized search input before repository access
• update the user management page with debounced username search, role/status filters, server total, and 20/50/100 page sizes
• preserve existing create, enable/disable, password reset, and password-hash redaction behavior

Why

The page previously loaded every Studio account in one request and had no way to narrow a growing inventory. This also made it inconsistent with the cloud credential and data source management pages, which are server-paginated.

Tests

• focused backend: AuthServiceDatabaseTest,StudioUserControllerTest — 13 tests passed
• backend full suite: 1,555 tests passed; Checkstyle 0 violations
• focused frontend: API and user-management page — 2 files / 3 tests passed
• full frontend suite: 98 files / 670 tests passed; one unrelated ClusterPage test initially timed out under full-suite load, then its file passed in isolation with 15/15 tests
• npm run lint -- --quiet: 0 errors (3 pre-existing warnings)
• npm run build: passed
• git diff --check: passed

Production changes: 198 additions / 19 deletions across backend and frontend, naturally exceeding 100 production lines without test padding.

Closes #2540

[RockteMQ-AI]

Summary

This PR modifies 8 file(s) with +532 -19 lines. Found 1 critical issue(s) that should be addressed before merging.

Findings

• [CRITICAL] diff:1 — Potential hardcoded credentials detected. Ensure secrets are not committed and use environment variables or secret management.

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Automated review by github-manager-bot

Additional notes (not anchored to a changed line)

• [CRITICAL] diff:1 — Potential hardcoded credentials detected. Ensure secrets are not committed and use environment variables or secret management. (line outside diff)

[RockteMQ-AI]

Summary

This PR adds server-side pagination for Studio user management with search, role filter, and status filter. Clean implementation — proper database-level pagination via MyBatis-Plus Page, thorough input validation (page/pageSize/search length bounds), and excellent test coverage across both backend and frontend.

The frontend race-condition handling with requestSeqRef and the edge-case recovery (empty page beyond last page → auto-correct) are well done.

LGTM — no blocking issues.

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Automated review by github-manager-bot