PLAN.md: the Files edge sweep

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

PLAN.md

@@ -774,6 +774,25 @@ something long in one, switch away and back, refresh — it's all still there.
   - *Not done, on purpose:* no restart-from-a-seek beyond what is encoded (the encode is
     faster than watching; a seek far ahead waits), no bit-rate ladder or adaptive
     switching, no subtitles, no keeping a finished re-encode for next time.
+- **Files edge sweep** — **2026-10-11** (v0.1.0-214), asked for as "a full bug sweep of
+  the Files section, every example and edge case". Every handler and both UI files read
+  through with odd inputs in mind, then a battery of ~60 requests against the live hub
+  (`sweep.py`, not kept: listings of files, missing and forbidden paths, NUL bytes, names
+  with spaces/#/%/?/umlauts, links to files, folders and nothing, a pipe, over-size saves,
+  uploads with bad names and clashes, renames and moves onto things, protected paths,
+  thumbnails of empty and mislabelled images, playback of an image and an audio-only mp4,
+  root-mode variants). One real data bug: **a save over the 8 MiB cap truncated the file
+  and kept the first 8 MiB, answering 204** — the body is now read whole first and refused
+  with 413, the file untouched. The rest: a link to a file showed the link's own time; a
+  link to nothing read as an empty 200; a bad codec or size was answered by inspecting
+  the file; a failed stream was handed back to the next identical request; a player
+  leaving mid-start made the recipe loop try the next engine; a root-mode ffmpeg's end
+  could wait forever; a page closing kept its stream for ten minutes (a beacon now
+  releases it at once); the path box took only absolute paths (it resolves like a shell
+  now, in the tab and the Move picker, with a test); a dropped folder became a nameless
+  empty file; the upload toast counted intentions; the viewer called a pipe a binary
+  file. Not bugs, left alone: `rm -rf` of a mount point empties it (the console is
+  root-capable by design); a folder of ten thousand rows is slow (no virtual list).
 - **Docker read-only view** — `docker ps`/logs; dockhand stays the source of truth.
 - **Notifications** — push on service failure / SMART warning / UPS event.
 - **Terminal extras** — search, copy-mode, font/theme, split panes, upload via