feat(ui): file browser and connection string builder dialogs (#44)

Enter on File Path inputs opens a file browser (load/save, extension
filter, hidden toggle, overwrite confirm). Enter on Connection String
inputs opens a builder for PostgreSQL, MSSQL and SQLite with masked
password/preview, parsing and optional connection test.

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

pkg/ui/connstring_test.go

@@ -0,0 +1,143 @@
+package ui
+
+import (
+	"reflect"
+	"strings"
+	"testing"
+)
+
+func TestBuildConnString(t *testing.T) {
+	tests := []struct {
+		name   string
+		fields ConnFields
+		mask   bool
+		want   string
+	}{
+		{
+			name:   "postgres defaults with db",
+			fields: func() ConnFields { f := DefaultConnFields(ConnPostgres); f.Database = "app"; return f }(),
+			want:   "postgres://postgres@localhost:5432/app?sslmode=disable",
+		},
+		{
+			name:   "postgres password unmasked",
+			fields: ConnFields{Kind: ConnPostgres, Host: "db", Port: "5433", Database: "x", User: "u", Password: "p@ss/w", SSLMode: "require"},
+			want:   "postgres://u:p%40ss%2Fw@db:5433/x?sslmode=require",
+		},
+		{
+			name:   "postgres password masked",
+			fields: ConnFields{Kind: ConnPostgres, Host: "db", Port: "5432", Database: "x", User: "u", Password: "secret"},
+			mask:   true,
+			want:   "postgres://u:****@db:5432/x",
+		},
+		{
+			name:   "mssql",
+			fields: ConnFields{Kind: ConnMSSQL, Host: "sql", Port: "1433", Database: "shop", User: "sa", Password: "pw", SSLMode: "disable"},
+			want:   "sqlserver://sa:pw@sql:1433?database=shop&encrypt=disable",
+		},
+		{
+			name:   "sqlite is the plain path",
+			fields: ConnFields{Kind: ConnSQLite, FilePath: "/tmp/a b.db"},
+			want:   "/tmp/a b.db",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := BuildConnString(tt.fields, tt.mask); got != tt.want {
+				t.Errorf("got %q, want %q", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestMaskedBuildHidesPassword(t *testing.T) {
+	f := ConnFields{Kind: ConnMSSQL, Host: "h", User: "u", Password: "hunter2"}
+	if got := BuildConnString(f, true); strings.Contains(got, "hunter2") {
+		t.Errorf("masked string leaks password: %q", got)
+	}
+}
+
+func TestParseConnString(t *testing.T) {
+	tests := []struct {
+		name string
+		in   string
+		want ConnFields
+	}{
+		{
+			name: "postgres full",
+			in:   "postgres://u:p%40ss@db:5433/app?sslmode=require&application_name=x",
+			want: ConnFields{Kind: ConnPostgres, Host: "db", Port: "5433", Database: "app", User: "u", Password: "p@ss", SSLMode: "require"},
+		},
+		{
+			name: "postgresql scheme, default port",
+			in:   "postgresql://u@db/app",
+			want: ConnFields{Kind: ConnPostgres, Host: "db", Port: "5432", Database: "app", User: "u"},
+		},
+		{
+			name: "mssql",
+			in:   "sqlserver://sa:pw@sql:1444?database=shop&encrypt=true",
+			want: ConnFields{Kind: ConnMSSQL, Host: "sql", Port: "1444", Database: "shop", User: "sa", Password: "pw", SSLMode: "true"},
+		},
+		{
+			name: "sqlite path",
+			in:   "/data/app.db",
+			want: ConnFields{Kind: ConnSQLite, FilePath: "/data/app.db"},
+		},
+		{
+			name: "sqlite scheme",
+			in:   "sqlite:///data/app.db",
+			want: ConnFields{Kind: ConnSQLite, FilePath: "/data/app.db"},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := ParseConnString(tt.in, ConnPostgres)
+			if err != nil {
+				t.Fatal(err)
+			}
+			got.Extra = nil
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("got %+v, want %+v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestParseConnStringEmptyUsesHintDefaults(t *testing.T) {
+	got, err := ParseConnString("  ", ConnMSSQL)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got.Kind != ConnMSSQL || got.Port != "1433" || got.Host != "localhost" {
+		t.Errorf("unexpected defaults: %+v", got)
+	}
+}
+
+func TestParseConnStringInvalid(t *testing.T) {
+	if _, err := ParseConnString("postgres://u:p@host:badport/db", ConnPostgres); err == nil {
+		t.Error("expected error for invalid port")
+	}
+}
+
+func TestConnStringRoundTrip(t *testing.T) {
+	for _, in := range []string{
+		"postgres://u:pw@db:5433/app?application_name=x&sslmode=require",
+		"sqlserver://sa:pw@sql:1433?application+name=x&database=shop&encrypt=false",
+	} {
+		f, err := ParseConnString(in, ConnPostgres)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if got := BuildConnString(f, false); got != in {
+			t.Errorf("round trip: got %q, want %q", got, in)
+		}
+	}
+}
+
+func TestTestConnectionSQLite(t *testing.T) {
+	if err := TestConnection(ConnFields{Kind: ConnSQLite}); err == nil {
+		t.Error("expected error for empty path")
+	}
+	if err := TestConnection(ConnFields{Kind: ConnSQLite, FilePath: t.TempDir() + "/missing.db"}); err == nil {
+		t.Error("expected error for missing file")
+	}
+}