fix: reconcile retry on rule processing errors

[dorodb-web22]

Description

processNodeAgainstAllRules had no return value, so Reconcile always returned ctrl.Result{}, nil even when rule evaluation or status patch calls failed. This caused the workqueue to treat every reconciliation as successful, skipping backoff and requeue on transient errors. Node taint state could drift silently until an unrelated event triggered a new reconcile.

This change makes processNodeAgainstAllRules return an aggregated error via errors.Join and propagates it through Reconcile, consistent with how RuleReconciler.processAllNodesForRule already handles errors.

Adds a regression test that simulates a status patch failure using the interceptor pattern and verifies Reconcile returns a non-nil error.

Related Issue

Fixes #220

Type of Change

/kind bug

Testing

make test
make lint

Checklist

• make test passes
• make lint passes

Does this PR introduce a user-facing change?

NONE

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This pull-request has been approved by: dorodb-web22
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• ✅ login: dorodb-web22 / name: Dorothy (4ed6af1, e83982e)

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Hi @dorodb-web22. Thanks for your PR.

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[Karthik-K-N]

Nice addition, Thank you

[Karthik-K-N]

we are just checking if there is expected error and we are never checking workqueue length, its assumption that it requeue.
Do you think its better to rename test?

[dorodb-web22]

Good point! i renamed it to "should return an error when rule status patch fails". since we're just checking the error returned rather than inspecting the workqueue directly, this is definitely more accurate.

[Karthik-K-N]

/ok-to-test