Add pause/resume, within-part byte-range resume; bump to 0.0.3

Split the single morphing button into a green/amber play-pause (Update →
Pause → Resume) and a red stop (Cancel). Pause aborts the download but
keeps the partial (resumable); Cancel aborts and deletes. Backend gets a
separate pause flag distinct from cancel.

Resume now continues WITHIN a part: the partially-written piece is fetched
from its last byte via an HTTP byte range (with a safe fall back to
re-fetching the whole piece if the CDN ignores the range), instead of
re-downloading the whole part. A title is resumable as soon as any bytes
are on disk.

Version bumped to 0.0.3 (no release tagged).

README.md

@@ -79,7 +79,7 @@ http://<console-ip>:12880/
 
 ## Status
 
-0.0.2, early. Title scan, source classification, version resolution,
+0.0.3, early. Title scan, source classification, version resolution,
 firmware-compatibility filtering, target/storage-id handling, and the local
 AppInstUtil HTTP stream have been verified on firmware 11.60. PatchDL now
 downloads PS5 update manifests as merged piece packages under `/data/patchdl`;