cache beacons per epoch to avoid repeated queries to node service

[poszu]

Part of #6676

[codecov]

Codecov Report

Attention: Patch coverage is 65.62500% with 11 lines in your changes missing coverage. Please review.

Project coverage is 77.1%. Comparing base (d4b6405) to head (6045b8d).
Report is 5 commits behind head on node-split-poc.

✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
hare3/remote.go	0.0%	5 Missing ⚠️
node/smeshing_service.go	0.0%	4 Missing ⚠️
api/node/models/models.go	0.0%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@              Coverage Diff               @@
##           node-split-poc   #6679   +/-   ##
==============================================
  Coverage            77.0%   77.1%           
==============================================
  Files                 385     386    +1     
  Lines               53652   53660    +8     
==============================================
+ Hits                41357   41411   +54     
+ Misses               9824    9786   -38     
+ Partials             2471    2463    -8     

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