Add configuration revisions system and project variant deletion

Features:
- Configuration versioning: immutable snapshots in local_configuration_versions
- Revisions UI: /configs/:uuid/revisions page to view version history
- Clone from version: ability to clone configuration from specific revision
- Project variant deletion: DELETE /api/projects/:uuid endpoint
- Updated CLAUDE.md with new architecture details and endpoints

Architecture updates:
- local_configuration_versions table for immutable snapshots
- Version tracking on each configuration save
- Rollback capability to previous versions
- Variant deletion with main variant protection

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

internal/handlers/web.go

@@ -67,7 +67,7 @@ func NewWebHandler(templatesPath string, componentService *services.ComponentSer
 	}
 
 	// Load each page template with base
-	simplePages := []string{"login.html", "configs.html", "projects.html", "project_detail.html", "pricelists.html", "pricelist_detail.html"}
+	simplePages := []string{"login.html", "configs.html", "projects.html", "project_detail.html", "pricelists.html", "pricelist_detail.html", "config_revisions.html"}
 	for _, page := range simplePages {
 		pagePath := filepath.Join(templatesPath, page)
 		var tmpl *template.Template
@@ -197,6 +197,13 @@ func (h *WebHandler) ProjectDetail(c *gin.Context) {
 	})
 }
 
+func (h *WebHandler) ConfigRevisions(c *gin.Context) {
+	h.render(c, "config_revisions.html", gin.H{
+		"ActivePage": "configs",
+		"ConfigUUID": c.Param("uuid"),
+	})
+}
+
 func (h *WebHandler) Pricelists(c *gin.Context) {
 	h.render(c, "pricelists.html", gin.H{"ActivePage": "pricelists"})
 }