fix(launcher): resolve gateway startup issue in tui mode

The picoclaw-launcher-tui was not respecting PICOCLAW_HOME and PICOCLAW_CONFIG
environment variables when determining the config file path. This caused a
configuration mismatch between the TUI and the gateway command when these
environment variables were set.

Changes:
- Updated ConfigPath() to check PICOCLAW_CONFIG environment variable first
- Updated ConfigDir() to check PICOCLAW_HOME environment variable first
- Added comprehensive unit tests for both functions
- Added documentation comments explaining the priority order

This ensures that launcher-tui and gateway command use the same config file
path resolution logic, fixing the issue where gateway could not start from TUI.

Fixes #1704

cmd/picoclaw-launcher-tui/internal/config/store.go

@@ -13,7 +13,12 @@ const (
 	configFileName = "config.json"
 )
 
+// ConfigPath returns the path to the config file.
+// Priority: $PICOCLAW_CONFIG > $PICOCLAW_HOME/config.json > ~/.picoclaw/config.json
 func ConfigPath() (string, error) {
+	if configPath := os.Getenv("PICOCLAW_CONFIG"); configPath != "" {
+		return configPath, nil
+	}
 	dir, err := ConfigDir()
 	if err != nil {
 		return "", err
@@ -21,7 +26,12 @@ func ConfigPath() (string, error) {
 	return filepath.Join(dir, configFileName), nil
 }
 
+// ConfigDir returns the directory for picoclaw configuration.
+// Priority: $PICOCLAW_HOME > ~/.picoclaw
 func ConfigDir() (string, error) {
+	if home := os.Getenv("PICOCLAW_HOME"); home != "" {
+		return home, nil
+	}
 	home, err := os.UserHomeDir()
 	if err != nil {
 		return "", err

cmd/picoclaw-launcher-tui/internal/config/store_test.go

@@ -0,0 +1,134 @@
+package configstore
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func TestConfigPath_Default(t *testing.T) {
+	// Clear environment variables
+	os.Unsetenv("PICOCLAW_CONFIG")
+	os.Unsetenv("PICOCLAW_HOME")
+
+	got, err := ConfigPath()
+	if err != nil {
+		t.Fatalf("ConfigPath() error = %v", err)
+	}
+
+	home, _ := os.UserHomeDir()
+	want := filepath.Join(home, ".picoclaw", "config.json")
+	if got != want {
+		t.Errorf("ConfigPath() = %q, want %q", got, want)
+	}
+}
+
+func TestConfigPath_WithPICOCLAW_CONFIG(t *testing.T) {
+	// Set PICOCLAW_CONFIG
+	customPath := "/custom/path/config.json"
+	os.Setenv("PICOCLAW_CONFIG", customPath)
+	defer os.Unsetenv("PICOCLAW_CONFIG")
+
+	os.Unsetenv("PICOCLAW_HOME")
+
+	got, err := ConfigPath()
+	if err != nil {
+		t.Fatalf("ConfigPath() error = %v", err)
+	}
+
+	if got != customPath {
+		t.Errorf("ConfigPath() = %q, want %q", got, customPath)
+	}
+}
+
+func TestConfigPath_WithPICOCLAW_HOME(t *testing.T) {
+	// Clear PICOCLAW_CONFIG, set PICOCLAW_HOME
+	os.Unsetenv("PICOCLAW_CONFIG")
+	customHome := "/custom/home"
+	os.Setenv("PICOCLAW_HOME", customHome)
+	defer os.Unsetenv("PICOCLAW_HOME")
+
+	got, err := ConfigPath()
+	if err != nil {
+		t.Fatalf("ConfigPath() error = %v", err)
+	}
+
+	want := filepath.Join(customHome, "config.json")
+	if got != want {
+		t.Errorf("ConfigPath() = %q, want %q", got, want)
+	}
+}
+
+func TestConfigDir_Default(t *testing.T) {
+	os.Unsetenv("PICOCLAW_HOME")
+
+	got, err := ConfigDir()
+	if err != nil {
+		t.Fatalf("ConfigDir() error = %v", err)
+	}
+
+	home, _ := os.UserHomeDir()
+	want := filepath.Join(home, ".picoclaw")
+	if got != want {
+		t.Errorf("ConfigDir() = %q, want %q", got, want)
+	}
+}
+
+func TestConfigDir_WithPICOCLAW_HOME(t *testing.T) {
+	customHome := "/custom/picoclaw/home"
+	os.Setenv("PICOCLAW_HOME", customHome)
+	defer os.Unsetenv("PICOCLAW_HOME")
+
+	got, err := ConfigDir()
+	if err != nil {
+		t.Fatalf("ConfigDir() error = %v", err)
+	}
+
+	if got != customHome {
+		t.Errorf("ConfigDir() = %q, want %q", got, customHome)
+	}
+}
+
+func TestConfigPath_Priority(t *testing.T) {
+	// PICOCLAW_CONFIG should take priority over PICOCLAW_HOME
+	configPath := "/priority/config.json"
+	homePath := "/priority/home"
+
+	os.Setenv("PICOCLAW_CONFIG", configPath)
+	os.Setenv("PICOCLAW_HOME", homePath)
+	defer func() {
+		os.Unsetenv("PICOCLAW_CONFIG")
+		os.Unsetenv("PICOCLAW_HOME")
+	}()
+
+	got, err := ConfigPath()
+	if err != nil {
+		t.Fatalf("ConfigPath() error = %v", err)
+	}
+
+	if got != configPath {
+		t.Errorf("ConfigPath() = %q, want %q (PICOCLAW_CONFIG should have priority)", got, configPath)
+	}
+}
+
+// Windows-specific test for case-insensitive comparison
+func TestConfigPath_Windows(t *testing.T) {
+	if os.PathSeparator != '\\' {
+		t.Skip("Skipping Windows-specific test on non-Windows platform")
+	}
+
+	os.Unsetenv("PICOCLAW_CONFIG")
+	os.Unsetenv("PICOCLAW_HOME")
+
+	got, err := ConfigPath()
+	if err != nil {
+		t.Fatalf("ConfigPath() error = %v", err)
+	}
+
+	home, _ := os.UserHomeDir()
+	want := filepath.Join(home, ".picoclaw", "config.json")
+	if !strings.EqualFold(got, want) {
+		t.Errorf("ConfigPath() = %q, want %q", got, want)
+	}
+}