Implement Phase 1 of KAT (#1)

**Phase 1: State Management & Leader Election**
*   **Goal**: A functional embedded etcd and leader election mechanism.
*   **Tasks**:
    1.  Implement the `StateStore` interface (RFC 5.1) with an etcd backend (`internal/store/etcd.go`).
    2.  Integrate embedded etcd server into `kat-agent` (RFC 2.2, 5.2), configurable via `cluster.kat` parameters.
    3.  Implement leader election using `go.etcd.io/etcd/client/v3/concurrency` (RFC 5.3).
    4.  Basic `kat-agent init` functionality:
        *   Parse `cluster.kat`.
        *   Start single-node embedded etcd.
        *   Campaign for and become leader.
        *   Store initial cluster configuration (UID, CIDRs from `cluster.kat`) in etcd.
*   **Milestone**:
    *   A single `kat-agent init --config cluster.kat` process starts, initializes etcd, and logs that it has become the leader.
    *   The cluster configuration from `cluster.kat` can be verified in etcd using an etcd client.
    *   `StateStore` interface methods (`Put`, `Get`, `Delete`, `List`) are testable against the embedded etcd.

Reviewed-on: #1

internal/config/parse.go

@@ -7,6 +7,7 @@ import (
 	"os"
 
 	pb "git.dws.rip/dubey/kat/api/v1alpha1"
+	"github.com/davecgh/go-spew/spew"
 	"gopkg.in/yaml.v3"
 
 	"encoding/json"
@@ -64,6 +65,8 @@ func ParseClusterConfiguration(filePath string) (*pb.ClusterConfiguration, error
 		return nil, fmt.Errorf("failed to unmarshal spec into proto: %w", err)
 	}
 
+	spew.Dump(&config) // For debugging, remove in production
+
 	SetClusterConfigDefaults(&config)
 
 	if err := ValidateClusterConfiguration(&config); err != nil {