refactor: poa fixes, tweaks, and chores

[Reecepbcups]

• Also migrates all int64 -> uint64 to just a sdkmath.NewIntFromUint64(uint64) consumer, rather than type converting. Makes linter happy :)

[Reecepbcups]

Simulation test failure is due to the new logic for denying duplicate ba78c0c

Will fix later. Other CI 2 failures are unrelated. Main e2e & test run as expected

[codecov]

Codecov Report

Attention: Patch coverage is 70.76923% with 19 lines in your changes missing coverage. Please review.

Project coverage is 58.46%. Comparing base (6922e22) to head (ac705e9).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
keeper/msg_server.go	57.89%	10 Missing and 6 partials ⚠️
simulation/operations.go	62.50%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #237      +/-   ##
==========================================
- Coverage   60.01%   58.46%   -1.56%     
==========================================
  Files          44       44              
  Lines        2116     2754     +638     
==========================================
+ Hits         1270     1610     +340     
- Misses        662      956     +294     
- Partials      184      188       +4     

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