Refactor model architecture introduce base model and database model separation

[armanist]

This PR introduces a breaking refactor of the model layer (QtModel → DbModel + base Model).
Database fetch methods now return new model instances, and create() resets model state to prevent identity leakage.

Please review any code that:

reuses model instances across operations

relies on implicit state mutation after first() / findOne() / findOneBy() / get()

assumes IDs are preserved between create() calls

See CHANGELOG.md for details.

Closes #372

[codecov]

Codecov Report

❌ Patch coverage is 90.86957% with 21 lines in your changes missing coverage. Please review.
✅ Project coverage is 80.84%. Comparing base (f84b1b8) to head (50267de).
⚠️ Report is 9 commits behind head on master.

Files with missing lines	Patch %	Lines
src/Model/Traits/SoftDeletes.php	0.00%	8 Missing ⚠️
src/Model/Exceptions/ModelException.php	0.00%	4 Missing ⚠️
src/Model/DbModel.php	97.18%	2 Missing ⚠️
src/Console/Commands/KeyGenerateCommand.php	0.00%	1 Missing ⚠️
src/Console/Commands/MigrationMigrateCommand.php	0.00%	1 Missing ⚠️
src/Console/Commands/ModuleGenerateCommand.php	0.00%	1 Missing ⚠️
src/Libraries/Cron/CronLock.php	87.50%	1 Missing ⚠️
...es/Storage/Adapters/GoogleDrive/GoogleDriveApp.php	0.00%	1 Missing ⚠️
src/Libraries/Storage/UploadedFile.php	0.00%	1 Missing ⚠️
src/Model/Helpers/model.php	90.90%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master     #410      +/-   ##
============================================
+ Coverage     80.65%   80.84%   +0.18%     
- Complexity     2641     2669      +28     
============================================
  Files           237      238       +1     
  Lines          7020     7114      +94     
============================================
+ Hits           5662     5751      +89     
- Misses         1358     1363       +5     

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