feat(api,web): remove a movie, files optional

`DELETE /api/movies/{id}` took the row and left the files, and no
surface exposed it. It now accepts `delete_files`, which unlinks the
title's §7.4 folder — atomic, so sidecars go with the feature. Targets
come from `media_files`, never from re-deriving the folder name, and a
path outside its root is never touched. The torrent is untouched (§7.3):
it keeps seeding and the reaper owns it.

The release deck grows a quiet REMOVE control opening one inline
confirmation: file count, size and folder first, then a delete-files
toggle that starts off, then what the choice costs.

Closes #104

.impeccable/surfaces/web-src-main-ts.md

@@ -30,6 +30,18 @@ reads the library as derived status, not flags.
   per-title override (rule→override mapping in releases.ts — bookkeeping,
   never policy; verdicts always come from the API). Esc steps back one
   layer: deck → search results → board.
+- Removal (§7.4, issue 104): REMOVE is a quiet control in the deck head,
+  never a row affordance — a dense list is the wrong place for a delete.
+  It opens one inline confirmation carrying the evidence first (file count,
+  total size, the §7.4 folder as reported by `/api/movies/{id}/files`), then
+  the decision, then the cost. "delete files from disk" is a separate toggle
+  that starts OFF and stays disabled when nothing is on disk or the file list
+  cannot be read; armed, the panel, its toggle word, the note and the confirm
+  button all turn caution amber, and the confirm reads "remove and delete
+  files" instead of "remove from library". The note says what does not happen
+  either: the torrent keeps seeding (§7.3). Esc abandons the confirmation
+  before it abandons the deck. On success the deck closes and the surface it
+  opened over repaints, so a removed title never lingers in a list.
 - Library view (§4.2, issue #32): the LIBRARY rail control opens the library
   deck — SERIES then MOVIES groups. Status is derived and only displayed
   (§4.2 status chips in the channel-violet/neutral family for series, state