flatten scrape config to 'sites:'

* flatten scrape config to 'sites:'. Update unit tests and readme.
* remove check for file_extensions configuration. 
* show progress indication after 5 seconds.
* add documentation to functions
* fix: remove MaxDepth and link extraction functionality
* fix: Remove MaxDepth references from cmd/web.go

internal/config/config.go

@@ -7,35 +7,64 @@ import (
 	"gopkg.in/yaml.v2"
 )
 
+// Config represents the configuration for the rollup tool
 type Config struct {
-	FileTypes     []string     `yaml:"file_types"`
-	Ignore        []string     `yaml:"ignore"`
-	CodeGenerated []string     `yaml:"code_generated"`
-	Scrape        ScrapeConfig `yaml:"scrape"`
-}
-
-type ScrapeConfig struct {
-    Sites             []SiteConfig `yaml:"sites"`
-    OutputType        string       `yaml:"output_type"`
-    RequestsPerSecond float64      `yaml:"requests_per_second"`
-    BurstLimit        int          `yaml:"burst_limit"`
+	// FileExtensions is a list of file extensions to include in the rollup
+	FileExtensions []string `yaml:"file_extensions"`
+
+	// IgnorePaths is a list of glob patterns for paths to ignore
+	IgnorePaths []string `yaml:"ignore_paths"`
+
+	// CodeGeneratedPaths is a list of glob patterns for code-generated files
+	CodeGeneratedPaths []string `yaml:"code_generated_paths"`
+
+	// Sites is a list of site configurations for web scraping
+	Sites []SiteConfig `yaml:"sites"`
+
+	// OutputType specifies how the output should be generated
+	OutputType string `yaml:"output_type"`
+
+	// RequestsPerSecond limits the rate of web requests
+	RequestsPerSecond *float64 `yaml:"requests_per_second,omitempty"`
+
+	// BurstLimit sets the maximum burst size for rate limiting
+	BurstLimit *int `yaml:"burst_limit,omitempty"`
 }
 
+// SiteConfig contains configuration for scraping a single site
 type SiteConfig struct {
-    BaseURL          string            `yaml:"base_url"`
-    CSSLocator       string            `yaml:"css_locator"`
-    ExcludeSelectors []string          `yaml:"exclude_selectors"`
-    MaxDepth         int               `yaml:"max_depth"`
-    AllowedPaths     []string          `yaml:"allowed_paths"`
-    ExcludePaths     []string          `yaml:"exclude_paths"`
-    OutputAlias      string            `yaml:"output_alias"`
-    PathOverrides    []PathOverride    `yaml:"path_overrides"`
+	// BaseURL is the starting point for scraping this site
+	BaseURL string `yaml:"base_url"`
+
+	// CSSLocator is used to extract specific content
+	CSSLocator string `yaml:"css_locator"`
+
+	// ExcludeSelectors lists CSS selectors for content to exclude
+	ExcludeSelectors []string `yaml:"exclude_selectors"`
+
+	// AllowedPaths lists paths that are allowed to be scraped
+	AllowedPaths []string `yaml:"allowed_paths"`
+
+	// ExcludePaths lists paths that should not be scraped
+	ExcludePaths []string `yaml:"exclude_paths"`
+
+	// OutputAlias provides an alternative name for output files
+	OutputAlias string `yaml:"output_alias"`
+
+	// PathOverrides allows for path-specific configurations
+	PathOverrides []PathOverride `yaml:"path_overrides"`
 }
 
+// PathOverride allows for path-specific configurations
 type PathOverride struct {
-    Path             string   `yaml:"path"`
-    CSSLocator       string   `yaml:"css_locator"`
-    ExcludeSelectors []string `yaml:"exclude_selectors"`
+	// Path is the URL path this override applies to
+	Path string `yaml:"path"`
+
+	// CSSLocator overrides the site-wide CSS locator for this path
+	CSSLocator string `yaml:"css_locator"`
+
+	// ExcludeSelectors overrides the site-wide exclude selectors for this path
+	ExcludeSelectors []string `yaml:"exclude_selectors"`
 }
 
 func Load(configPath string) (*Config, error) {
@@ -50,15 +79,28 @@ func Load(configPath string) (*Config, error) {
 		return nil, fmt.Errorf("error parsing config file: %v", err)
 	}
 
+	if err := config.Validate(); err != nil {
+		return nil, fmt.Errorf("invalid configuration: %v", err)
+	}
+
 	return &config, nil
 }
 
-func DefaultConfigPath() string {
-	return "rollup.yml"
-}
+// Validate checks the configuration for any invalid values
+func (c *Config) Validate() error {
+	if c.RequestsPerSecond != nil && *c.RequestsPerSecond <= 0 {
+		return fmt.Errorf("requests_per_second must be positive")
+	}
 
-func FileExists(filename string) bool {
-	_, err := os.Stat(filename)
-	return err == nil
-}
+	if c.BurstLimit != nil && *c.BurstLimit <= 0 {
+		return fmt.Errorf("burst_limit must be positive")
+	}
 
+	for _, site := range c.Sites {
+		if site.BaseURL == "" {
+			return fmt.Errorf("base_url must be specified for each site")
+		}
+	}
+
+	return nil
+}