feat(configure): edit every config option in the configurator

After the NetBox instances, netssh configure now opens a menu with all
sections: SSH defaults, global SSH options (jump host, host key
checking, target, address family, extra args, -o options), SSH rules,
resolver & cache (including the cache file), shortcuts & command alias,
and completion.max_results. SSH options can also be set per instance.

The wizard rebuilt the config from its own fields, so re-running it
dropped global SSH options, ssh.rules and completion.max_results from
the file. It now edits a copy of the loaded config, and save validates
SSH options and rules before writing.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/setup/wizard_test.go

@@ -455,3 +455,46 @@ func TestSaveKeepsSSHOptions(t *testing.T) {
 		t.Fatalf("ssh settings lost:\n%+v\n%+v", loaded.SSH, loaded.NetBoxes[0].SSH)
 	}
 }
+
+// Re-running the configurator must keep settings that have no form field of
+// their own or were not touched in the menu.
+func TestPrepareKeepsUnmanagedSettings(t *testing.T) {
+	cfg := config.Config{
+		NetBox: config.NetBoxConfig{URL: "https://legacy.example", Token: "t"},
+		SSH: config.SSHConfig{
+			DefaultUser: "root",
+			SSHOptions:  config.SSHOptions{ProxyJump: "jh.example.com", Options: map[string]string{"forwardagent": "yes"}},
+			Rules:       []config.SSHRule{{Match: config.SSHMatch{Tag: "dmz"}, SSHOptions: config.SSHOptions{ProxyJump: "none"}}},
+		},
+		Completion: config.CompletionConfig{MaxResults: 50},
+		Cache:      config.CacheConfig{Path: "/var/cache/netssh/hosts.json"},
+	}
+	sources := []config.NetBoxConfig{{Name: "default", URL: "https://legacy.example", Token: "t"}}
+	got := prepare(cfg, sources)
+
+	if !reflect.DeepEqual(got.SSH, cfg.SSH) || got.Completion != cfg.Completion || got.Cache.Path != cfg.Cache.Path {
+		t.Fatalf("settings lost: %+v", got)
+	}
+	if got.NetBox.URL != "" || !reflect.DeepEqual(got.NetBoxes, sources) {
+		t.Fatalf("legacy instance not migrated: %+v / %+v", got.NetBox, got.NetBoxes)
+	}
+	if !reflect.DeepEqual(got.Resolver.Strategies, []string{"primary_ip"}) || got.Cache.TTL != 3600 {
+		t.Fatalf("defaults missing: %+v %+v", got.Resolver, got.Cache)
+	}
+}
+
+func TestSaveRejectsInvalidSSHOptions(t *testing.T) {
+	t.Setenv("XDG_CONFIG_HOME", t.TempDir())
+	t.Setenv("HOME", t.TempDir())
+	cfg := config.Config{
+		NetBoxes: []config.NetBoxConfig{{Name: "prod", URL: "https://prod.example", Token: "t"}},
+		Resolver: config.ResolverConfig{Strategies: []string{"primary_ip"}},
+		SSH:      config.SSHConfig{Rules: []config.SSHRule{{SSHOptions: config.SSHOptions{ProxyJump: "none"}}}},
+	}
+	if err := save(cfg); err == nil {
+		t.Fatal("rule without match was saved")
+	}
+	if _, err := os.Stat(config.Path()); !os.IsNotExist(err) {
+		t.Fatalf("config file written despite error: %v", err)
+	}
+}