fix: migrate scanner stream to redisson and refine audit status labels`

[XiaoSeS]

Summary

This PR contains two focused fixes on the scanner-fix branch:

1. Migrate the security scan Redis Stream path from Spring Data Redis Stream APIs to Redisson
2. Refine security audit status labels in the web UI

Changes

Backend: Redis Stream -> Redisson

Only the scanner stream slice was migrated. Existing Redis usage for session, rate limiting, idempotency, and other non-stream scenarios remains unchanged.

• add direct org.redisson:redisson dependency
• add standalone RedissonClient configuration without introducing redisson-spring-boot-starter
• migrate scan task producer to Redisson RStream
• refactor stream consumer to use Redisson consumer group APIs
• handle existing consumer groups safely instead of treating BUSYGROUP as an error
• add pending-message reclaim using autoClaim
• expose reclaim-related stream settings in application config
• add focused tests for Redisson config and stream producer/consumer behavior
• remove the old Spring Redis stream producer implementation

Frontend: security audit display labels

Adjust audit status rendering so incomplete scans do not appear as suspicious.

• when scan is not completed yet, display 扫描中 / Scanning
• change blocked wording from 已拦截 / Blocked to 高风险 / High Risk
• add display-state helper for audit badge rendering
• update related component and locale tests

Verification

Passed:

• focused backend scanner stream tests
• make test-web

Notes:

• make test still fails in skillhub-notification
• failure is unrelated to this PR and is caused by Mockito inline mock maker on the current JDK 25 environment:
  • Could not initialize inline Byte Buddy mock maker
  • Could not self-attach to current VM using external process

Risk / Impact

• backend impact is limited to the scanner Redis Stream path
• non-stream Redis usage is intentionally unchanged
• frontend change only affects audit status presentation and wording