fix(fuse,cli): let rm, rename and mkdir take paths in on-demand folders

`pdfs rm ~/Downloads/x` answered "is not under the mountpoint" while
`pdfs move` took the same path: the Delete, Rename and CreateFolder
handlers still read paths against the primary mount only (B88).

They now go through `route_change`, the router ResolveConflict already
used, renamed from `route_conflict`. It answers the request in the
inode space of the mount that owns the path.

An on-demand folder's root has a parent on Drive, so `pdfs rm
~/Downloads` would have trashed the whole synced folder from under its
mount. rm and rename refuse a path that names a mount's root.

crates/pdfs-cli/src/main.rs

@@ -285,7 +285,8 @@ enum Command {
     },
     /// Rename a file or folder via the running daemon.
     Rename {
-        /// File/folder path, inside the mountpoint or relative to it.
+        /// File/folder path, inside My files or an on-demand synced folder, or
+        /// relative to the mountpoint.
         path: PathBuf,
         /// New name (a single path component).
         new_name: String,
@@ -304,12 +305,14 @@ enum Command {
     },
     /// Trash a file or folder via the running daemon.
     Rm {
-        /// File/folder path, inside the mountpoint or relative to it.
+        /// File/folder path, inside My files or an on-demand synced folder, or
+        /// relative to the mountpoint.
         path: PathBuf,
     },
     /// Create a folder via the running daemon.
     Mkdir {
-        /// Parent folder path, inside the mountpoint or relative to it.
+        /// Parent folder path, inside My files or an on-demand synced folder,
+        /// or relative to the mountpoint.
         parent: PathBuf,
         /// New folder name (a single path component).
         name: String,