feat: support overrideHost configuration for ratelimit, event reporter and stat modules

[SkyeBeFreeman]

Summary

• Add limiterOverrideHost property to PolarisRateLimitProperties for overriding remote rate limiter service host
• Add overrideHost property to PushGatewayEventReporterProperties for overriding push gateway event reporter host
• Add pushGatewayOverrideHost property to PolarisStatProperties for overriding Prometheus push gateway host
• All three properties allow replacing discovered instance IPs with a specified host while preserving original ports
• Updated corresponding ConfigModifier classes to propagate the new settings to polaris-java SDK
• Added unit tests for all new properties and config modifiers

Test plan

• Unit tests added for PolarisRateLimitProperties, RateLimitConfigModifier
• Unit tests added for PushGatewayEventReporterProperties, PushGatewayEventReporterConfigModifier
• Unit tests added for PolarisStatProperties, StatConfigModifier
• Run full CI (JUnit + Checkstyle + License Header)

🤖 Generated with Claude Code

[fuyuwei01]

LGTM

[codecov]

Codecov Report

❌ Patch coverage is 83.33333% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 54.64%. Comparing base (fe5a32b) to head (2a03be2).
⚠️ Report is 1 commits behind head on 2024.

Files with missing lines	Patch %	Lines
...enhancement/stat/config/PolarisStatProperties.java	33.33%	2 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               2024    #1804      +/-   ##
============================================
+ Coverage     54.62%   54.64%   +0.02%     
  Complexity      152      152              
============================================
  Files           482      482              
  Lines         14089    14101      +12     
  Branches       1765     1765              
============================================
+ Hits           7696     7706      +10     
- Misses         5776     5778       +2     
  Partials        617      617              

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