feat: watch the profiles that declare no files

An empty file list is the one assertion here that ages unwatched. Nothing
can go missing and no ref can drift, so nothing notices when a core that
embedded everything grows a path. virtualjaguar said "No external BIOS
files are required or loaded by this core" while its source had grown
eleven filenames read from the system directory, and only a reading
found it.

fileless_audit looks for the request itself, the system directory ask, in
the sources each profile already cites. Over the 151 fileless profiles it
named eleven, of which two were covered by data_directories, six carried
an exclusion_note, and three had nothing written down at all: craft
writes its world database in that directory, dice stores the answer in a
variable no other file in the tree names, lutro hands it to the Lua game.
Each now says so.

The check settles: declared files, a declared directory, or a written
answer all end it, so what it reports is the set nobody has read yet. A
test holds the corpus at zero.

emulators/craft.yml

@@ -9,6 +9,12 @@ core_version: "v1"
 display_name: "Minecraft (Craft)"
 cores: [craft]
 systems: []
+exclusion_note: >
+  The system directory is asked for, and what goes in it is written by the
+  core: g->db_path and g->db_auth_path, the world database and its auth
+  table. Nothing is read from it that the user has to supply
+  (src/main.c:2682-2697).
+
 files: []
 notes: >
   Libretro port of Craft, a simple Minecraft clone by Michael Fogleman.

emulators/dice.yml

@@ -22,6 +22,11 @@ notes: |
   dummy launcher files. The system directory is retrieved but never used
   for file loading (libretro.cpp:60-62).
 
+exclusion_note: >
+  The system directory is asked for and stored in retro_base_directory, which
+  is named in no other file of the tree and read nowhere: the answer is never
+  used (libretro.cpp:28,60-63).
+
 files: []
 
 analysis:

emulators/lutro.yml

@@ -22,4 +22,9 @@ notes: |
   (filesystem.c:296) but does not load any files from it itself.
   No BIOS, firmware, or system files required.
 
+exclusion_note: >
+  The system directory is not read by the core but handed to the Lua game
+  through fs_getAppdataDirectory, so whatever is loaded from it is the game's
+  own content, not a file this core names (filesystem.c:291-303).
+
 files: []