upload: Name the link based on the uploaded filename.

We previously parsed the filename as stored on disk, which is rather
sanitized.  Use as close to the original filename as possible.

web/src/upload.ts

@@ -372,10 +372,13 @@ export function setup_upload(config: Config): Uppy {
 
     uppy.on("upload-success", (file, response) => {
         assert(file !== undefined);
-        const {url} = z.object({url: z.string()}).parse(response.body);
-        const split_url = url.split("/");
-        const filename = split_url.at(-1);
-        const syntax_to_insert = "[" + filename + "](" + url + ")";
+        const {url, filename} = z
+            .object({url: z.string(), filename: z.string()})
+            .parse(response.body);
+        // Our markdown does not have escape characters, so we cannot link any text with brackets;
+        // strip them out, if present.
+        const filtered_filename = filename.replaceAll("[", "").replaceAll("]", "");
+        const syntax_to_insert = "[" + filtered_filename + "](" + url + ")";
         const $text_area = config.textarea();
         const replacement_successful = compose_ui.replace_syntax(
             get_translated_status(file),

web/tests/upload.test.js

@@ -501,6 +501,7 @@ test("uppy_events", ({override_rewire, mock_template}) => {
     let response = {
         body: {
             url: "/user_uploads/4/cb/rue1c-MlMUjDAUdkRrEM4BTJ/copenhagen.png",
+            filename: "copenhagen.png",
         },
     };