🐛 Validate debug files with their own pointer loader

The `/dbg/actions` file validation passed the file id where
`get-resolved-file-libraries` expects the file map, so the library map
was seeded with a nil key. It also validated a file read without
realizing it, so the first page lookup of a pointer-mapped file raised
"load is not supported when *load-fn* is not bind" and the endpoint
could not validate exactly the files the feature touches.

Read the file realized (validation walks every page and component
anyway) and build the library map from the file. The library loader
already resolves each library's pointers with its own id, so the
realized file and its libraries validate as plain data. Covered by a
handler-level test that fails before the change.

AI-assisted-by: deepseek-v4.1-flash

backend/src/app/http/debug.clj

@@ -784,8 +784,12 @@
 
     (db/tx-run! (assoc cfg ::db/rollback true)
                 (fn [cfg]
-                  (let [file (bfc/get-file cfg file-id)
-                        libs (bfc/get-resolved-file-libraries cfg file-id)]
+                  ;; Validation walks every page and component, so the
+                  ;; file is read realized; the library map is built
+                  ;; from the file (not its id) and its own loader
+                  ;; resolves each library's pointers.
+                  (let [file (bfc/get-file cfg file-id :realize? true)
+                        libs (bfc/get-resolved-file-libraries cfg file)]
                     (if file
                       (let [errors (cfv/validate-file file libs)]
                         {::yres/status  200

backend/test/backend_tests/http_debug_test.clj

@@ -0,0 +1,29 @@
+;; This Source Code Form is subject to the terms of the Mozilla Public
+;; License, v. 2.0. If a copy of the MPL was not distributed with this
+;; file, You can obtain one at http://mozilla.org/MPL/2.0/.
+;;
+;; Copyright (c) KALEIDOS SUBSIDIARY SL
+
+(ns backend-tests.http-debug-test
+  "The /dbg validate action walks the whole file and its libraries: it
+  must hand `get-resolved-file-libraries` the file (not its id) and
+  resolve the pointer-mapped pages with the file's own loader."
+  (:require
+   [app.http.debug :as debug]
+   [backend-tests.helpers :as th]
+   [clojure.test :as t]
+   [yetti.response :as-alias yres]))
+
+(t/use-fixtures :once th/state-init)
+(t/use-fixtures :each th/database-reset)
+
+(t/deftest validate-file-action-resolves-pointer-mapped-data
+  (let [profile (th/create-profile* 1)
+        file    (th/create-file* 1 {:profile-id (:id profile)
+                                    :project-id (:default-project-id profile)
+                                    :is-shared false})
+        handler (deref #'debug/validate-file)
+        result  (handler th/*system* {:params {:file-id (str (:id file))}})]
+
+    (t/is (= 200 (::yres/status result)))
+    (t/is (= "NO VALIDATION ERRORS FOUND" (::yres/body result)))))