feat: add update tenant endpoint with rate limiter cache invalidation

[faranjit]

• Add PATCH /tenants/{id} endpoint to update tenant settings
• Refactor RateLimiter to struct with functional options pattern
• Add callback mechanism for cross-component communication
• Invalidate rate limiter cache immediately on tenant update
• Add UpdateTenant to store interface and postgres implementation
• Add comprehensive tests for update flow and callback verification

[codecov]

Codecov Report

❌ Patch coverage is 85.71429% with 10 lines in your changes missing coverage. Please review.
✅ Project coverage is 67.28%. Comparing base (1e83a2d) to head (6cefbd9).
⚠️ Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
internal/controller/server.go	0.00%	6 Missing ⚠️
internal/controller/handlers/tenants.go	87.50%	2 Missing and 1 partial ⚠️
internal/store/postgres/tenants.go	94.44%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main       #6      +/-   ##
==========================================
+ Coverage   66.60%   67.28%   +0.68%     
==========================================
  Files          36       36              
  Lines        2045     2103      +58     
==========================================
+ Hits         1362     1415      +53     
- Misses        590      594       +4     
- Partials       93       94       +1     

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