Refactor architecture: eliminate auto-discovery and consolidate packages

- Remove auto-discovery entirely (~450 lines)
  * Delete internal/content/discoverer.go
  * Simplify enhancer to single-phase processing
  * Remove duplicate container expansion logic

- Consolidate repository implementations
  * Move internal/content/client.go → internal/db/http_client.go
  * Group all repository implementations in db/ package

- Add file utilities to engine following Go stdlib patterns
  * Add engine.ProcessFile() and ProcessDirectory() methods
  * Engine now handles both content processing AND file operations

- Move site management to dedicated package
  * Move internal/content/site_manager.go → internal/sites/manager.go
  * Clear separation of site lifecycle from content processing

- Preserve container expansion (syntactic sugar)
  * .insertr on containers still auto-applies to viable children
  * Container detection logic consolidated in engine/utils.go

Result: Clean architecture with single source of truth for .insertr processing

cmd/serve.go

@@ -17,9 +17,9 @@ import (
 	"github.com/insertr/insertr/internal/api"
 	"github.com/insertr/insertr/internal/auth"
 	"github.com/insertr/insertr/internal/config"
-	"github.com/insertr/insertr/internal/content"
 	"github.com/insertr/insertr/internal/db"
 	"github.com/insertr/insertr/internal/engine"
+	"github.com/insertr/insertr/internal/sites"
 )
 
 var serveCmd = &cobra.Command{
@@ -76,14 +76,14 @@ func runServe(cmd *cobra.Command, args []string) {
 	}
 
 	// Create legacy auth config for compatibility
-	authConfig := &auth.AuthConfig{
+	authConfig := &config.AuthConfig{
 		DevMode:   cfg.Auth.DevMode,
 		Provider:  cfg.Auth.Provider,
 		JWTSecret: cfg.Auth.JWTSecret,
 	}
 
 	if cfg.Auth.OIDC != nil {
-		authConfig.OIDC = &auth.OIDCConfig{
+		authConfig.OIDC = &config.OIDCConfig{
 			Endpoint:     cfg.Auth.OIDC.Endpoint,
 			ClientID:     cfg.Auth.OIDC.ClientID,
 			ClientSecret: cfg.Auth.OIDC.ClientSecret,
@@ -107,7 +107,7 @@ func runServe(cmd *cobra.Command, args []string) {
 
 	// Initialize site manager with auth provider
 	authProvider := &engine.AuthProvider{Type: cfg.Auth.Provider}
-	siteManager := content.NewSiteManagerWithAuth(contentClient, cfg.Auth.DevMode, authProvider)
+	siteManager := sites.NewSiteManagerWithAuth(contentClient, cfg.Auth.DevMode, authProvider)
 
 	// Convert config sites to legacy format and register
 	var legacySites []*config.SiteConfig
@@ -120,7 +120,7 @@ func runServe(cmd *cobra.Command, args []string) {
 			AutoEnhance: site.AutoEnhance,
 		}
 		if site.Discovery != nil {
-			legacySite.Discovery = &content.DiscoveryConfig{
+			legacySite.Discovery = &config.DiscoveryConfig{
 				Enabled:    site.Discovery.Enabled,
 				Aggressive: site.Discovery.Aggressive,
 				Containers: site.Discovery.Containers,