Regex for includeNamespaces / excludeNamespaces

## Overview
Allow `includeNamespaces` / `excludeNamespaces` in the kubescape-operator
config to accept regex patterns in addition to exact namespace names.

## Problem
From a scalable standpoint, it would be nice to create a regex so that we can have dynamic namespaces.

## Solution
includeNamespaces: "kube-system" # unchanged, exact match
includeNamespacesRegex: "^team-.*-prod$" # new, RE2 regex
excludeNamespaces: [...]
excludeNamespacesRegex: [...]

A namespace is included if it matches any entry in either list; excluded likewise. Patterns use Go's `regexp` (RE2) and are compiled once at config load — invalid patterns fail fast with a clear error.

## Alternatives
**Flux GitOps workaround**: a CronJob with namespace list/get RBAC resolves the regex against live cluster state every N minutes and writes the matched names to a ConfigMap. The HelmRelease references it via `spec.valuesFrom`, so Flux re-renders the chart whenever the list changes.

## Additional context
- Related: kubescape/helm-charts#664 (dynamic reconfiguration without redeploy)
- Example would be how prometheus handles namespaces for alerts

Start at the operator's config-loading and namespace-selection paths, then trace how includeNamespaces and excludeNamespaces are parsed and applied. Add coverage for exact names, regex matches, include/exclude behavior, and invalid RE2 patterns; done means patterns are compiled during config load and invalid configuration fails with a clear error.

Written by the indexing model from the issue text.