Add rm -r for folders, and make ls list one folder level

rm -r FOLDER deletes a folder and everything under it, records and
objects, so the space is freed. It lists what will go (the first 20
names, then a count) with the total size and asks on the terminal; no
answer or no terminal deletes nothing. -f skips the question and makes a
missing name a no-op, -rf and -fr combine them, and rm -r / is refused.
Objects still in use are worked out once per delete, not once per file.

ls now shows one level, like ls(1): sub-folders once with a trailing
slash, their total size and newest date, then the files, with names
relative to the folder. list keeps the recursive listing of full names
that scripts pipe through cut -c31-, and ls -r is the same.

Docs, man pages, the guide (new rm-r screenshot) and README follow.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/guide/shots.py

@@ -266,8 +266,9 @@ def main():
     shoot("add", t)
 
     t = Term(box)
+    t.cmd("vault ls", P)
+    t.cmd("vault ls letters", P)
     t.cmd("vault list", P)
-    t.cmd("vault list letters", P)
     shoot("list", t)
 
     t = Term(box)
@@ -315,6 +316,18 @@ def main():
     t.cmd("ls Scans")
     shoot("migrate", t)
 
+    # rm -r: lists the folder, asks, then frees the space
+    t = Term(box)
+    t.cmd("vault ls", P)
+    t.lines.append(prompt() + '<span class="c">vault rm -r receipts</span>')
+    for line in box.run_tty("vault rm -r receipts", P, "y").split("\n"):
+        esc = html.escape(line)
+        if "[y/N]" in line:
+            esc = '<span class="hl">%s</span>' % esc
+        t.lines.append(esc)
+    t.cmd("vault ls", P)
+    shoot("rm-r", t)
+
     # absorb: a tar archive piped in, here pulled from a gzipped tarball
     box.write("Projects/website/index.html", "<h1>hello</h1>\n")
     box.write("Projects/website/css/site.css", "body{}\n")