refactor: resolve eslint warnings (max-statements, complexity)

[btlghrants]

Description

Refactor to eliminate eslint warnings: max-statements, complexity in src/lib/controller/index.ts.

Related Issue

Relates to #1248

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Other (security config, docs update, etc)

Checklist before merging

• Unit, Journey, E2E Tests, docs, adr added or updated as needed
• Contributor Guide Steps followed

[codecov]

Codecov Report

Attention: Patch coverage is 44.44444% with 15 lines in your changes missing coverage. Please review.

Project coverage is 79.17%. Comparing base (847ec6e) to head (0104d02).

Files with missing lines	Patch %	Lines
src/lib/controller/index.ts	6.25%	15 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1486      +/-   ##
==========================================
+ Coverage   78.56%   79.17%   +0.60%     
==========================================
  Files          38       39       +1     
  Lines        1717     1719       +2     
  Branches      410      388      -22     
==========================================
+ Hits         1349     1361      +12     
- Misses        339      356      +17     
+ Partials       29        2      -27     

Files with missing lines	Coverage Δ
src/lib/controller/index.util.ts	100.00% <100.00%> (ø)
src/lib/controller/index.ts	10.83% <6.25%> (+1.53%)	⬆️

... and 6 files with indirect coverage changes

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[btlghrants]

The controller index file didn't have direct unit test coverage before I started refactoring it, but I did what I could: I added tests around the lines I had to move to cut the complexity rating, but tried not to touch anything else.

The file's still failing short of the 78.xx% codecov goal but I got it from 0% to 40-something% and I think this is probably the best place to stop (for now). Doing more is going to require some non-trivial rework and that feels a bit out of scope for the thread I'm currently pulling.