rebase: apply audit bug fixes on latest main

Rebased fix/1.0-audit-bugs onto current main (post-merge of PRs #119, #127).

Changes:
- Custom domain types: docker.ImageID, docker.ContainerID, webhook.UnparsedURL
- Type-safe function signatures throughout docker/deploy/webhook packages
- Remove docker-compose.yml, test helper files
- README and Dockerfile updates
- Prettier-formatted JS files

internal/handlers/app.go

@@ -72,7 +72,7 @@ func (h *Handlers) HandleAppCreate() http.HandlerFunc { //nolint:funlen // valid
 		nameErr := validateAppName(name)
 		if nameErr != nil {
 			data["Error"] = "Invalid app name: " + nameErr.Error()
-			_ = tmpl.ExecuteTemplate(writer, "app_new.html", data)
+			h.renderTemplate(writer, tmpl, "app_new.html", data)
 
 			return
 		}
@@ -228,7 +228,7 @@ func (h *Handlers) HandleAppUpdate() http.HandlerFunc { //nolint:funlen // valid
 				"App":   application,
 				"Error": "Invalid app name: " + nameErr.Error(),
 			}, request)
-			_ = tmpl.ExecuteTemplate(writer, "app_edit.html", data)
+			h.renderTemplate(writer, tmpl, "app_edit.html", data)
 
 			return
 		}
@@ -239,7 +239,7 @@ func (h *Handlers) HandleAppUpdate() http.HandlerFunc { //nolint:funlen // valid
 				"App":   application,
 				"Error": "Invalid repository URL: " + repoURLErr.Error(),
 			}, request)
-			_ = tmpl.ExecuteTemplate(writer, "app_edit.html", data)
+			h.renderTemplate(writer, tmpl, "app_edit.html", data)
 
 			return
 		}