Add: CCR gas planning

[Rolf-Smit]

GasPlanner now handles closed-circuit segments separately from open-circuit. Oxygen usage is calculated based on metabolic rate and diluent usage on loop expansion during descent.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 93.93939% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 18.09%. Comparing base (ba2792b) to head (a95a725).

Files with missing lines	Patch %	Lines
...otech/app/abysner/domain/gasplanning/GasPlanner.kt	93.75%	0 Missing and 4 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #126      +/-   ##
==========================================
+ Coverage   17.64%   18.09%   +0.44%     
==========================================
  Files         134      134              
  Lines        6743     6780      +37     
  Branches      745      753       +8     
==========================================
+ Hits         1190     1227      +37     
+ Misses       5461     5460       -1     
- Partials       92       93       +1     

Flag	Coverage Δ
domain	78.19% <93.93%> (+0.66%)	⬆️
presentation	4.60% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.