feat: place files outside the bios tree

A platform that binds part of a standalone layout leaves the entries no
binding covers in a folder outside the BIOS tree: they are no longer
packed at the BIOS root, and the manifest names them (root: emulator,
outside_bios_folder). A launcher that executes a profile's file binds
the program folder: in the BIOS tree, below the roms directory a registry
entry names (root: roms, installed into the folder holding the BIOS
folder), or nowhere a pack reaches. A moved entry resolves by its own
path as well as by its destination.

uae4all gains kick.rom and rom.key in its working directory and loses a
not_bundled_on that named Recalbox, which runs uae4all-rpi. lexaloffle
declares that its programs read beside their executable, lists the
Windows build RetroBat runs and the pico8_dyn ROCKNIX runs on x86_64.

scripts/slots.py

@@ -228,7 +228,7 @@ def profile_claims(
                 # outside the BIOS tree, where no platform declares a file.
                 if outside_gap_scope(entry, is_standalone) or read_from_save_dir(
                     entry, is_standalone
-                ):
+                ) or entry.get("unplaced"):
                     continue
                 # A member of a romset is not a file at the BIOS root: the archive
                 # holding it occupies the destination (_archive_claims). Claiming
@@ -306,6 +306,7 @@ def _archive_claims(
         if isinstance(entry, dict)
         and not outside_gap_scope(entry, is_standalone)
         and not read_from_save_dir(entry, is_standalone)
+        and not entry.get("unplaced")
     ]
     prefix = profile.get("archive_prefix", "")
     claims: list[Claim] = []