Install native games as Ports, not ROMs

The store could only offer what an emulator boots, which meant cartridges
and nothing else — a little under half the catalog. Batocera runs Linux
and its Ports system takes .sh launchers, so a native build can be
installed too; it just is not a ROM.

`install: "port"` unpacks the zip, finds the executable and writes a
launcher that cd's into its directory first, because a game loads assets
relative to the working directory. Python's extraction drops the
executable bit, so it is restored from the mode the archive records.

The payload lives under ports/.data/<subfolder>/, whose leading dot is
what hides it from EmulationStation, while the launchers sit in a normal
subfolder that gets scanned like any other system's. Both carry the store
subfolder, so an uninstall or prune cannot reach another store's files —
verified by pointing a state entry at a foreign namespace and watching it
be refused.

Verified end to end on aarch64 against the live catalog: bevydemo
installs as a port with an executable launcher and binary, re-syncs
without re-downloading 29 MB, and uninstalls taking its 106 MB payload
with it. `install` defaults to rom, so existing configs are unaffected.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

config.example.json

@@ -8,29 +8,47 @@
       "download": "/api/download"
     }
   },
-
   "paths": {
     "roms_root": "/userdata/roms",
     "subfolder": "example"
   },
-
   "emulationstation": {
     "folder_name": "Example Store",
     "restart": true
   },
-
   "catalog": {
-    "statuses": ["released", "archived"],
+    "statuses": [
+      "released",
+      "archived"
+    ],
     "owner_id": null,
     "only": [],
     "exclude": []
   },
-
   "platforms": {
-    "c64": { "system": "c64", "kind": "cartridge", "ext": ".prg", "enabled": true },
-    "tic80": { "system": "tic80", "kind": "cartridge", "ext": ".tic", "enabled": true }
+    "c64": {
+      "system": "c64",
+      "kind": "cartridge",
+      "ext": ".prg",
+      "enabled": true
+    },
+    "tic80": {
+      "system": "tic80",
+      "kind": "cartridge",
+      "ext": ".tic",
+      "enabled": true
+    },
+    "bevy": {
+      "system": "ports",
+      "install": "port",
+      "kind": {
+        "x86_64": "linux_x64",
+        "aarch64": "linux_arm64"
+      },
+      "ext": ".zip",
+      "enabled": false
+    }
   },
-
   "behavior": {
     "prune": true,
     "timeout": 30,