refactor: split large files with backwards-compatible re-exports

[iloveagent57]

• Split bffs/handlers.py (749 → 71 lines) by extracting learner portal handlers to bffs/learner_portal/handlers.py
• Split subsidy_access_policy/models.py (2276 → 2090 lines) by extracting PolicyGroupAssociation and ForcedPolicyRedemption to models_supporting.py
• Remove pylint skip-file directive from models.py and fix all pylint issues
• Fix bug: action variable used before assignment in assignment_request_redeem()
• Add missing docstrings to clean_spend_limit, SubsidyAccessPolicyRequestAssignmentMixin, and assignment_request_redeem
• Document module splitting pattern in docs/architecture-patterns.md

All existing imports continue to work via re-exports for backwards compatibility.

🤖 Generated with Claude Code

Merge checklist:

• ./manage.py makemigrations has been run
  • Note: This must be run if you modified any models.
    • It may or may not make a migration depending on exactly what you modified, but it should still be run.

Post merge:

• Ensure that your changes went out to the stage instance
• Deploy to prod instance

[Copilot]

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated 5 comments.

[codecov]

Codecov Report

❌ Patch coverage is 85.75581% with 49 lines in your changes missing coverage. Please review.
✅ Project coverage is 84.29%. Comparing base (0739e1a) to head (2c20f5b).

Files with missing lines	Patch %	Lines
...rprise_access/apps/bffs/learner_portal/handlers.py	86.69%	24 Missing and 9 partials ⚠️
...ss/apps/subsidy_access_policy/models_supporting.py	86.11%	6 Missing and 4 partials ⚠️
...rprise_access/apps/subsidy_access_policy/models.py	33.33%	6 Missing ⚠️

❌ Your patch check has failed because the patch coverage (85.75%) is below the target coverage (95.00%). You can increase the patch coverage or adjust the target coverage.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #133      +/-   ##
==========================================
+ Coverage   84.28%   84.29%   +0.01%     
==========================================
  Files         144      147       +3     
  Lines       12209    12230      +21     
  Branches     1162     1163       +1     
==========================================
+ Hits        10290    10309      +19     
- Misses       1598     1600       +2     
  Partials      321      321              

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[Copilot]

Pull request overview

Copilot reviewed 8 out of 8 changed files in this pull request and generated 3 comments.

[Copilot]

The class docstring refers to BaseLearnerHandler, but the class name is BaseLearnerPortalHandler. Update the docstring to reference the correct class name to avoid confusion when navigating the codebase.

Suggested change

	The `BaseLearnerHandler` extends `BaseHandler` and provides shared core functionality
	The `BaseLearnerPortalHandler` extends `BaseHandler` and provides shared core functionality

[Copilot]

can_approve() is defined on SubsidyAccessPolicy but calls assignment_request_can_allocate(), which is only provided by SubsidyAccessPolicyRequestAssignmentMixin (used by PerLearnerSpendCreditAccessPolicy). Instead of suppressing pylint with # pylint: disable=no-member, consider moving can_approve() onto the mixin / relevant policy subclass, or add a concrete implementation on the base class that fails fast with a clear error when BNR is enabled on an unsupported policy type.

[Copilot]

ForcedPolicyRedemption.subsidy_access_policy is nullable (on_delete=SET_NULL), but both policy_uuid and __str__ unconditionally dereference self.subsidy_access_policy.uuid, which will raise if the related policy is deleted. Guard for a null policy (or make the FK non-nullable if null should be impossible in practice).

Suggested change

	return self.subsidy_access_policy.uuid
	def __str__(self):
	return (
	f'<{self.__class__.__name__} policy_uuid={self.subsidy_access_policy.uuid}, '
	if self.subsidy_access_policy is None:
	return None
	return self.subsidy_access_policy.uuid
	def __str__(self):
	return (
	f'<{self.__class__.__name__} policy_uuid={self.policy_uuid}, '