refactor: split controller.go into focused files by concern

[bdehamer]

Summary

Splits the 682-line internal/controller/controller.go into four focused files organized by responsibility. No behavioral changes — pure structural refactoring.

New file layout

File	Lines	Responsibility
controller.go	~160	Types, interfaces, Controller struct, New(), newAPIClient(), Run()
handlers.go	~170	registerEventHandlers(), runWorker(), processNextItem(), startWorkers()
reconcile.go	~270	processEvent(), recordContainer(), deploymentExists(), getCacheKey()
pod.go	~130	createInformerFactory(), getARDeploymentName(), getContainerDigest(), getDeploymentName(), podToPartialMetadata()
config.go	42	Unchanged

Key changes

• registerEventHandlers() extracted from New() as a Controller method — the event handler closures now use c.workqueue instead of closing over a local queue variable.
• newAPIClient() extracted as a package-level helper to isolate API client construction from the controller constructor.
• startWorkers() extracted from Run() for clarity.

Testing

All existing unit and integration tests pass without modification. No test changes needed since all files remain in the same package.

[Copilot]

Pull request overview

Refactors the Kubernetes deployment-tracker controller by splitting the previous monolithic internal/controller/controller.go into smaller files organized by responsibility, aiming to keep behavior unchanged while improving readability and maintainability.

Changes:

• Extracted event handler registration and worker lifecycle logic into handlers.go.
• Extracted reconciliation / posting logic into reconcile.go.
• Extracted pod/informer helper utilities into pod.go and simplified controller.go to core wiring (New, Run, API client construction).

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
internal/controller/controller.go	Slimmed down to core types + constructor + API client creation + Run(), delegating handlers/workers elsewhere.
internal/controller/handlers.go	New file containing informer event handlers and queue worker processing logic.
internal/controller/reconcile.go	New file containing processEvent/recordContainer and caching logic for posts.
internal/controller/pod.go	New file containing informer factory creation + pod/container helper functions.

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[Copilot]

@bdehamer I've opened a new pull request, #70, to work on those changes. Once the pull request is ready, I'll request review from you.

[bdehamer]

This was a nice bug fix picked-up by Copilot during this refactor. Even if we decide not to merge this PR, we should apply this change (using DeletionHandlingMetaNamespaceKeyFunc in place of MetaNamespaceKeyFunc)

[ajbeattie]

Heads up, I'm probably about to merge this PR: #72

It adds/updates several functions/methods in controller.go, so it will probably have some conflicts with this refactor. I'm not 100% sure whether/how the new stuff will fit into the concept/file split proposed here, but hopefully it either fits or illuminates some other natural separation of functionality that can be further split out 😅