feat(config): Add support for env var configuration

This commit introduces support for two environment variables,
allowing users to override the default paths for picoclaw's home
directory and configuration file.

- `PICOCLAW_CONFIG`: Directly specifies the path to the `config.json` file.
This is initialised first, takes precedence over the hardcoded path, and is ideal
for containerized deployments or custom config management.

- `PICOCLAW_HOME`: Overrides the root directory for all picoclaw data, (except the config)
(e.g., `~/.picoclaw`). This is useful for portable installations or placing
data in non-standard locations.

This change provides greater flexibility for running picoclaw in various environments without
being tied to the default home directory structure.

cmd/picoclaw/internal/helpers.go

@@ -19,6 +19,9 @@ var (
 )
 
 func GetConfigPath() string {
+	if configPath := os.Getenv("PICOCLAW_CONFIG"); configPath != "" {
+		return configPath
+	}
 	home, _ := os.UserHomeDir()
 	return filepath.Join(home, ".picoclaw", "config.json")
 }

cmd/picoclaw/internal/helpers_test.go

@@ -95,3 +95,13 @@ func TestGetConfigPath_Windows(t *testing.T) {
 func TestGetVersion(t *testing.T) {
 	assert.Equal(t, "dev", GetVersion())
 }
+
+func TestGetConfigPath_WithEnv(t *testing.T) {
+	t.Setenv("PICOCLAW_CONFIG", "/tmp/custom/config.json")
+	t.Setenv("HOME", "/tmp/home") // Also set home to ensure env is preferred
+
+	got := GetConfigPath()
+	want := "/tmp/custom/config.json"
+
+	assert.Equal(t, want, got)
+}

pkg/config/config_test.go

@@ -442,3 +442,28 @@ func TestDefaultConfig_DMScope(t *testing.T) {
 		t.Errorf("Session.DMScope = %q, want 'per-channel-peer'", cfg.Session.DMScope)
 	}
 }
+
+func TestDefaultConfig_WorkspacePath_Default(t *testing.T) {
+	// Unset to ensure we test the default
+	t.Setenv("PICOCLAW_HOME", "")
+	// Set a known home for consistent test results
+	t.Setenv("HOME", "/tmp/home")
+
+	cfg := DefaultConfig()
+	want := filepath.Join("/tmp/home", ".picoclaw", "workspace")
+
+	if cfg.Agents.Defaults.Workspace != want {
+		t.Errorf("Default workspace path = %q, want %q", cfg.Agents.Defaults.Workspace, want)
+	}
+}
+
+func TestDefaultConfig_WorkspacePath_WithPicoclawHome(t *testing.T) {
+	t.Setenv("PICOCLAW_HOME", "/custom/picoclaw/home")
+
+	cfg := DefaultConfig()
+	want := "/custom/picoclaw/home/workspace"
+
+	if cfg.Agents.Defaults.Workspace != want {
+		t.Errorf("Workspace path with PICOCLAW_HOME = %q, want %q", cfg.Agents.Defaults.Workspace, want)
+	}
+}

pkg/config/defaults.go

@@ -5,12 +5,29 @@
 
 package config
 
+import (
+	"os"
+	"path/filepath"
+)
+
 // DefaultConfig returns the default configuration for PicoClaw.
 func DefaultConfig() *Config {
+	// Determine the base path for the workspace.
+	// Priority: $PICOCLAW_HOME > ~/.picoclaw
+	var homePath string
+	if picoclawHome := os.Getenv("PICOCLAW_HOME"); picoclawHome != "" {
+		homePath = picoclawHome
+	} else {
+		userHome, _ := os.UserHomeDir()
+		homePath = filepath.Join(userHome, ".picoclaw")
+	}
+	workspacePath := filepath.Join(homePath, "workspace")
+
 	return &Config{
 		Agents: AgentsConfig{
 			Defaults: AgentDefaults{
-				Workspace:           "~/.picoclaw/workspace",
+				Workspace:           workspacePath,
+
 				RestrictToWorkspace: true,
 				Provider:            "",
 				Model:               "",