fix: don't declare Accept-Ranges: none for binary files

The server set Accept-Ranges: none on every file response. For text we
anonymize on the fly so byte ranges aren't meaningful, but binary
entries pass through unchanged — and the explicit "none" header makes
some browsers refuse to play <video>/<audio> elements that would
otherwise fall back to a full download. Newly uploaded MP4s under the
inline-preview threshold rendered as a blank progress bar (#538).

Only set Accept-Ranges: none for text entries; let binary entries omit
it so the standard fallback kicks in.

Fixes #538.

src/core/AnonymizedFile.ts

@@ -271,7 +271,16 @@ export default class AnonymizedFile {
         } else if (isTextFile(this.anonymizedPath)) {
           res.contentType("text/plain");
         }
-        res.header("Accept-Ranges", "none");
+        // For text files we anonymize on the fly and the output length can
+        // differ from the upstream, so byte ranges aren't meaningful — keep
+        // Accept-Ranges: none. For binary files (images, video, archives)
+        // the transformer is a passthrough, so omitting the explicit "none"
+        // lets <video>/<audio> elements use the standard fallback to a full
+        // download instead of refusing to play (#538).
+        const isTextEntry = isTextFile(this.anonymizedPath) === true;
+        if (isTextEntry) {
+          res.header("Accept-Ranges", "none");
+        }
         anonymizer.once("transform", (data) => {
           if (!mime && data.isText) {
             res.contentType("text/plain");

src/streamer/route.ts

@@ -66,7 +66,13 @@ router.post("/", async (req: express.Request, res: express.Response) => {
     } else if (isTextFile(filePath)) {
       res.contentType("text/plain");
     }
-    res.header("Accept-Ranges", "none");
+    // Only declare Accept-Ranges: none for text files — they get rewritten on
+    // the fly so byte ranges aren't meaningful. For binary entries the
+    // transformer is a passthrough; let <video>/<audio> fall back to a full
+    // download instead of refusing to play (#538).
+    if (isTextFile(filePath)) {
+      res.header("Accept-Ranges", "none");
+    }
     anonymizer.once("transform", (data) => {
       if (!mime && data.isText) {
         res.contentType("text/plain");