🐛 Normalize error response on duplicate file ID

Capture unique constraint violation in insert-file! and return
generic :not-found error instead of propagating raw PostgreSQL
exception, preventing file existence oracle.

AI-assisted-by: mimo-v2.5-pro

backend/src/app/binfile/common.clj

@@ -748,9 +748,17 @@
     (fmigr/upsert-migrations! conn file))
 
   (let [file (encode-file cfg file)]
-    (db/insert! conn :file
-                (file->params file)
-                (assoc opts ::db/return-keys false))
+    (try
+      (db/insert! conn :file
+                  (file->params file)
+                  (assoc opts ::db/return-keys false))
+      (catch org.postgresql.util.PSQLException cause
+        (if (db/duplicate-key-error? cause)
+          (ex/raise :type :not-found
+                    :code :object-not-found
+                    :hint "file already exists"
+                    :cause cause)
+          (throw cause))))
 
     (->> (file->file-data-params file)
          (fdata/upsert! cfg))

backend/test/backend_tests/rpc_file_test.clj

@@ -141,6 +141,31 @@
         (let [result (:result out)]
           (t/is (= 0 (count result))))))))
 
+(t/deftest create-file-with-duplicate-id
+  (let [prof    (th/create-profile* 1 {:is-active true})
+        proj-id (:default-project-id prof)
+        file-id (uuid/next)]
+
+    (t/testing "create file with specific id"
+      (let [data {::th/type :create-file
+                  ::rpc/profile-id (:id prof)
+                  :project-id proj-id
+                  :id file-id
+                  :name "first-file"}
+            out  (th/command! data)]
+        (t/is (nil? (:error out)))))
+
+    (t/testing "create file with duplicate id returns normalized error"
+      (let [data {::th/type :create-file
+                  ::rpc/profile-id (:id prof)
+                  :project-id proj-id
+                  :id file-id
+                  :name "duplicate-file"}
+            out  (th/command! data)
+            err  (:error out)]
+        (t/is (th/ex-info? err))
+        (t/is (th/ex-of-type? err :not-found))))))
+
 (t/deftest file-gc-with-fragments
   (let [profile (th/create-profile* 1)
         file    (th/create-file* 1 {:profile-id (:id profile)