feat: add the PCSX2 missing BIOS dialog screen

PCSX2 standalone shows a dialog and runs nothing without a BIOS: record 2026-10-27-fac0b52c9475 of the regions branch, reviewed on its PNG.

tests/campaign/oracle.yml

@@ -74,6 +74,15 @@ cores:
       - pattern: '^BIOS file ".*" could not be fully read'
         source_ref: mednafen/ss/ss.c:1978-1983 at 2ce77e20
     error_screens: []
+  "pcsx2":
+    note: >-
+      PCSX2 standalone (scripts/standalone_probe.py). Without a BIOS it shows a
+      dialog and runs nothing: the dialog is its error screen, captured as the
+      1280x720 root window.
+    error_patterns: []
+    error_screens:
+      - sha1: 46329c633ea7d0b63349261e4aab169e4f44d3f6
+        shows: the dialog "PCSX2 requires a PlayStation 2 BIOS in order to run"
   "PCSX1":
     note: An HLE BIOS stands in when none is found, and the run logs nothing about it.
     error_patterns: []

tests/test_core_probe.py

@@ -319,7 +319,8 @@ class OracleTests(unittest.TestCase):
             self.assertEqual(core_probe.judge(rep, saturn)[0], "bios_error", line)
         menu = {"Beetle PSX": "dfbfc299250c0983f86bbf951efd187441306d92",
                 "Beetle PSX HW": "dfbfc299250c0983f86bbf951efd187441306d92",
-                "SwanStation": "167fb7b6527e295b12dca5806a29856f5f31d401"}
+                "SwanStation": "167fb7b6527e295b12dca5806a29856f5f31d401",
+                "pcsx2": "46329c633ea7d0b63349261e4aab169e4f44d3f6"}
         for library, sha1 in menu.items():
             rep = {"loaded": True, "logs": [], "frames": 100, "warmup": 0,
                    "observables": {"frame_hashes": [[90, sha1]], "uniform_frames": []}}