Cleanup server store step interface

[6543]

make interface smaller, remove dead code, make it more secure

[woodpecker-bot]

Surge PR preview deployment was removed

[codecov]

Codecov Report

❌ Patch coverage is 50.00000% with 5 lines in your changes missing coverage. Please review.
✅ Project coverage is 41.23%. Comparing base (f1bf85f) to head (5c6fdce).
⚠️ Report is 4 commits behind head on main.

Files with missing lines	Patch %	Lines
server/api/pipeline.go	0.00%	3 Missing ⚠️
server/api/agent.go	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6476      +/-   ##
==========================================
- Coverage   41.25%   41.23%   -0.02%     
==========================================
  Files         431      431              
  Lines       28815    28788      -27     
==========================================
- Hits        11887    11872      -15     
+ Misses      15861    15848      -13     
- Partials     1067     1068       +1     

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