Refactor, Enhance: Condition parsing/resolving.

[Jeffset]

This CL fully separates parsing from validation,
as per the initial design:

Any `MayBeInvalid` model works on the best effort basis,
performing no additional checks at construction/usage time.
Thus, if the model is in fact invalid, the behavior is undefined.
All thorough checks are performed only at validation

This CL changes no behavior on the good path.
In case of condition parsing/resolution errors, some errors/warnings could be hidden by others before this CL. Now all of them should be reported correctly.

[codecov]

Codecov Report

Attention: Patch coverage is 88.46154% with 3 lines in your changes are missing coverage. Please review.

Project coverage is 83.80%. Comparing base (4b82b9d) to head (e054017).
Report is 1 commits behind head on main.

Files	Patch %	Lines
...ndex/yatagan/core/model/impl/ConditionModelImpl.kt	88.46%	0 Missing and 3 partials ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main     #162      +/-   ##
============================================
- Coverage     83.86%   83.80%   -0.07%     
- Complexity     1598     1607       +9     
============================================
  Files           197      197              
  Lines          7681     7650      -31     
  Branches       1448     1444       -4     
============================================
- Hits           6442     6411      -31     
+ Misses          729      727       -2     
- Partials        510      512       +2     

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