feat: packs leave out what the emulator installs

A file or tree installed with the emulator is already on the user's machine, so packs, install manifests and verify's pack count leave it out. bundled is scoped by mode like any entry: Dolphin's Sys and PPSSPP's assets ship with the standalone releases, not with the libretro cores, so they now follow the libretro build only and still reach RetroArch packs. PrimeHack, standalone only, ships its own Sys.

schemas/emulator.schema.json

@@ -272,6 +272,10 @@
               "both"
             ]
           },
+          "bundled": {
+            "type": "boolean",
+            "description": "Installed with the emulator for the build mode names, so packs leave the tree out."
+          },
           "source_ref": {
             "type": "string"
           }
@@ -443,7 +447,8 @@
             "type": "boolean"
           },
           "bundled": {
-            "type": "boolean"
+            "type": "boolean",
+            "description": "Installed with the emulator for the build mode names (all builds when mode is absent): already on the user's machine, so packs and install manifests leave it out."
           },
           "config_key": {
             "type": "string"