refactor(recipe): add ResolvedParams for better param handling

Introduce ResolvedParams field to Recipe struct for storing resolved
parameter values from defaults and user overrides. Update loader to
populate and use it for template rendering. Adjust runner to use
ResolvedParams for root path and generalize file discovery.

internal/recipe/loader.go

@@ -32,26 +32,26 @@ func Load(path string, userParams map[string]any) (*Recipe, error) {
 		return nil, fmt.Errorf("yaml parse: %w", err)
 	}
 
-	// Apply defaults
+	// Apply defaults + user --param overrides
 	if r.Parameters == nil {
 		r.Parameters = make(map[string]Parameter)
 	}
-	params := make(map[string]any)
+	r.ResolvedParams = make(map[string]any)
 	for name, p := range r.Parameters {
 		if v, ok := userParams[name]; ok {
-			params[name] = v
+			r.ResolvedParams[name] = v
 		} else if p.Default != nil {
-			params[name] = p.Default
+			r.ResolvedParams[name] = p.Default
 		}
 	}
 
-	// Render templates (so {{.package_path}} becomes "internal")
+	// Render templates with resolved values
 	tpl, err := template.New("recipe").Parse(string(parts[2]))
 	if err != nil {
 		return nil, err
 	}
 	var rendered bytes.Buffer
-	if err := tpl.Execute(&rendered, params); err != nil {
+	if err := tpl.Execute(&rendered, r.ResolvedParams); err != nil {
 		return nil, err
 	}
 	body := rendered.String()

internal/recipe/runner.go

@@ -85,15 +85,15 @@ Execute this step now. Respond ONLY with the expected output format — no expla
 func (r *Runner) discoverFiles() []string {
 	var files []string
 
-	// Get root from parameter or default
-	root := "internal"
-	if p, ok := r.Recipe.Parameters["package_path"]; ok {
-		if def, ok := p.Default.(string); ok && def != "" {
-			root = def
+	// Get root from --param or default
+	root := "."
+	if v, ok := r.Recipe.ResolvedParams["package_path"]; ok {
+		if s, ok := v.(string); ok && s != "" {
+			root = s
 		}
 	}
 
-	// Build set of allowed extensions from recipe frontmatter
+	// Build allowed extensions from recipe frontmatter
 	allowedExt := make(map[string]bool)
 	for _, lang := range r.Recipe.ProjectLanguages {
 		if exts, ok := r.Recipe.Extensions[lang]; ok {
@@ -107,10 +107,9 @@ func (r *Runner) discoverFiles() []string {
 		if err != nil || d.IsDir() {
 			return nil
 		}
-		ext := filepath.Ext(path)
-		if allowedExt[ext] {
+		if allowedExt[filepath.Ext(path)] {
 			b, _ := os.ReadFile(path)
-			if strings.Contains(string(b), "if err != nil") { // this is still Go-specific for now; we can generalize later
+			if strings.Contains(string(b), "if err != nil") {
 				files = append(files, path)
 			}
 		}

internal/recipe/types.go

@@ -7,10 +7,13 @@ type Recipe struct {
 	Parameters           map[string]Parameter `yaml:"parameters"`
 	AllowedShellCommands []string             `yaml:"allowed_shell_commands"`
 
-	// New fields for generic file discovery (option 2)
+	// Generic discovery support (option 2)
 	ProjectLanguages []string            `yaml:"project_languages"`
 	Extensions       map[string][]string `yaml:"extensions"`
 
+	// Resolved runtime values from --param flags
+	ResolvedParams map[string]any `yaml:"-"`
+
 	// Internal fields populated by loader
 	Overview           string `yaml:"-"`
 	Steps              []Step `yaml:"-"`