Add validation rules

[kddejong]

Summary

Adds validation rules:

• E3706: AutoScaling MaxSize must be >= MinSize
• Lambda Layers maxItems: 5 schema patch
• CloudWatch AlarmName no leading/trailing whitespace pattern
• AutoScaling duplicate instance types via uniqueKeys on Overrides

All constraints verified against real CloudFormation deployments and AWS documentation.

[codecov]

Codecov Report

❌ Patch coverage is 92.85714% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 93.48%. Comparing base (0bbabc9) to head (6ea4837).
⚠️ Report is 48 commits behind head on main.

Files with missing lines	Patch %	Lines
...les/resources/autoscaling/AutoScalingMinMaxSize.py	92.85%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4424      +/-   ##
==========================================
- Coverage   93.54%   93.48%   -0.06%     
==========================================
  Files         418      426       +8     
  Lines       14145    14433     +288     
  Branches     2817     2876      +59     
==========================================
+ Hits        13232    13493     +261     
- Misses        567      582      +15     
- Partials      346      358      +12     

Flag	Coverage Δ
unittests	93.48% <92.85%> (-0.05%)	⬇️

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