feat(BA-4866): extract RBACValidators injection to dependency layer

[fregataa]

Summary

• this work DOES NOT apply any validator to action processors.
• Create Validators and RBACValidators dataclasses for structured validator injection
• Wire validators through the DI layer (server.py, ProcessingComposer, ProcessorsDependency) into VFolderProcessors, following the same pattern as action_monitors
• Validators are injected but not yet applied to individual action processors (follow-up task)

Test plan

• pants fmt/fix/lint passed
• pants check (mypy) passed
• CI passes

Resolves BA-4866

[Copilot]

Pull request overview

This PR introduces a structured “validators” injection path (not yet applied to individual action processors) and wires RBAC validator instances from the DI layer down into VFolderProcessors, mirroring the existing action_monitors injection approach.

Changes:

• Add Validators / RBACValidators dataclasses for structured validator injection.
• Thread validators through server.py and the processing DI (ProcessingComposer → ProcessorsDependency → Processors.create()).
• Extend VFolderProcessors construction to accept validators.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
src/ai/backend/manager/services/vfolder/processors/vfolder.py	Accepts Validators in VFolderProcessors.__init__ (currently unused/dropped).
src/ai/backend/manager/services/processors.py	Adds validators to ProcessorArgs and passes it into VFolderProcessors.
src/ai/backend/manager/server.py	Constructs RBAC validators from permission_controller_repository and passes them into Processors.create().
src/ai/backend/manager/dependencies/processing/processors.py	Extends ProcessorsProviderInput to carry validators into ProcessorArgs.
src/ai/backend/manager/dependencies/processing/composer.py	Builds RBAC validators in the DI composer and passes them into ProcessorsDependency.
src/ai/backend/manager/actions/validators/rbac/init.py	Adds RBACValidators container.
src/ai/backend/manager/actions/validators/init.py	Adds top-level Validators container.

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[seedspirit]

I'm not sure define dataclass in __init__.py. I think init.py should only be used for importing things to make importing more convenient. What do others think? @jopemachine @HyeockJinKim

[jopemachine]

I think it would be better to keep things like types.py in a separate file.

[fregataa]

types.py is not a good idea because usually types modules should be the one that other modules depend on, not the one that depends on other modules

[jopemachine]

There are a large number of conflicts