kvm2: config block, constructor registration, IDs, state mapping and classify

The kvm2 block reuses KVMConfig; validateKVM gains a block-name variant so
messages say kvm2. The package skeleton has a non-dialing New, strict
providerID parsing, the state table and a 34-row classify test.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

internal/provider/config_kvm_test.go

@@ -214,6 +214,100 @@ providers:
 	}
 }
 
+func TestLoadConfig_kvm2Valid(t *testing.T) {
+	t.Parallel()
+	yaml := strings.Replace(validKVMYAML, "type: kvm\n    kvm:\n", "type: kvm2\n    kvm2:\n", 1)
+	cfg, err := LoadConfig([]byte(yaml))
+	if err != nil {
+		t.Fatalf("LoadConfig() error = %v, want nil", err)
+	}
+	if cfg.Providers[0].KVM != nil {
+		t.Errorf("providers[0].kvm = %+v, want nil", cfg.Providers[0].KVM)
+	}
+	k := cfg.Providers[0].KVM2
+	if k == nil {
+		t.Fatal("providers[0].kvm2 = nil")
+	}
+	if k.SSHKeyFile != "/etc/proxy-operator/kvm/id_ed25519" || k.KnownHostsFile != "/etc/proxy-operator/kvm/known_hosts" || k.DiskSizeGB != 20 {
+		t.Errorf("kvm2 = %+v, want sshKeyFile, knownHostsFile and diskSizeGb parsed", k)
+	}
+	if k.Images["ubuntu"].Format != "raw" {
+		t.Errorf("images[ubuntu].format = %q, want raw", k.Images["ubuntu"].Format)
+	}
+	if mt := k.MachineTypes["small"]; mt.VCPUs != 1 || mt.MemoryMiB != 1024 {
+		t.Errorf("machineTypes[small] = %+v, want {1 1024}", mt)
+	}
+	if len(k.Hosts) != 2 || k.Hosts[0].Name != "nas1" || k.Hosts[1].Pool != "fast" {
+		t.Errorf("hosts = %+v, want nas1 and lab2 with lab2's pool parsed", k.Hosts)
+	}
+}
+
+func TestLoadConfig_kvm2Invalid(t *testing.T) {
+	t.Parallel()
+	minimal := func(body string) string {
+		return "providers:\n  - name: kvm2-home\n    type: kvm2\n    kvm2:\n" + indent(body, 6)
+	}
+	hostsAndTypes := `
+machineTypes:
+  small: {vcpus: 1, memoryMiB: 1024}
+hosts:
+  - {name: nas1, address: nas1:22, user: virt, bridge: br0}
+`
+	tests := []struct {
+		name       string
+		yaml       string
+		wantErrSub string
+	}{
+		{
+			name:       "missing kvm2 block",
+			yaml:       "providers:\n  - name: kvm2-home\n    type: kvm2\n",
+			wantErrSub: "kvm2 block is required",
+		},
+		{
+			name:       "missing sshKeyFile",
+			yaml:       minimal("knownHostsFile: /kh\n" + hostsAndTypes),
+			wantErrSub: "kvm2.sshKeyFile is required",
+		},
+		{
+			name:       "missing knownHostsFile without insecure flag",
+			yaml:       minimal("sshKeyFile: /key\n" + hostsAndTypes),
+			wantErrSub: "kvm2.knownHostsFile is required unless kvm2.insecureIgnoreHostKey is true",
+		},
+		{
+			name:       "no machine types",
+			yaml:       minimal("sshKeyFile: /key\nknownHostsFile: /kh\nhosts:\n  - {name: nas1, address: nas1:22, user: virt, bridge: br0}\n"),
+			wantErrSub: "kvm2.machineTypes must define at least one",
+		},
+		{
+			name:       "no hosts",
+			yaml:       minimal("sshKeyFile: /key\nknownHostsFile: /kh\nmachineTypes:\n  small: {vcpus: 1, memoryMiB: 1024}\n"),
+			wantErrSub: "kvm2.hosts must list at least one host",
+		},
+		{
+			name:       "duplicate host name",
+			yaml:       minimal("sshKeyFile: /key\nknownHostsFile: /kh\nmachineTypes:\n  small: {vcpus: 1, memoryMiB: 1024}\nhosts:\n  - {name: nas1, address: a:22, user: virt, bridge: br0}\n  - {name: nas1, address: b:22, user: virt, bridge: br0}\n"),
+			wantErrSub: `kvm2.hosts[1]: duplicate host name "nas1"`,
+		},
+		{
+			name:       "image key with a slash",
+			yaml:       minimal("sshKeyFile: /key\nknownHostsFile: /kh\nimages:\n  ../etc/d: {url: https://x/y.qcow2}\n" + hostsAndTypes),
+			wantErrSub: `kvm2.images["../etc/d"]: key must be letters, digits, dots, dashes or underscores`,
+		},
+	}
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+			_, err := LoadConfig([]byte(tc.yaml))
+			if err == nil {
+				t.Fatalf("LoadConfig() error = nil, want error containing %q", tc.wantErrSub)
+			}
+			if !strings.Contains(err.Error(), tc.wantErrSub) {
+				t.Errorf("LoadConfig() error = %q, want substring %q", err.Error(), tc.wantErrSub)
+			}
+		})
+	}
+}
+
 func indent(s string, n int) string {
 	pad := strings.Repeat(" ", n)
 	lines := strings.Split(strings.TrimLeft(s, "\n"), "\n")