feat(alerter): allow configuring alerter to only watch alertrules in a specific namespace

[matucker-msft]

No description provided.

[Copilot]

Pull request overview

Adds optional namespace scoping to the alerter’s AlertRule discovery, allowing deployments to limit rule loading to a single Kubernetes namespace (while preserving the current “all namespaces” behavior by default).

Changes:

• Added --namespace CLI flag to configure which namespace the alerter loads AlertRules from.
• Threaded the namespace option through AlerterOpts into the rules store.
• Updated the rules store list call to apply client.InNamespace(...) when configured, and added unit tests covering both scoped and unscoped behavior.

Reviewed changes

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

File	Description
cmd/alerter/main.go	Adds --namespace flag and passes it into the alerter service options.
alerter/service.go	Extends AlerterOpts with Namespace and forwards it to the rules store.
alerter/rules/store.go	Filters the controller-runtime client List call by namespace when configured.
alerter/rules/store_test.go	Adds tests validating rule reload behavior for all namespaces vs a single namespace.