perf: read yaml through the c loader

Loading the emulator profiles is the most expensive step of every
command here, and all forty call sites used the pure-Python scanner
while libyaml sat unused in the same wheel. One shared yaml_load picks
the C loader when pyyaml ships it: the 375 profiles parse in 0.18s
instead of 1.39s, and verify --platform retroarch drops from 2.17s to
0.73s. The loader class is the same restricted one safe_load uses.

es_bios.xml was parsed straight from the network while install.py
already refused a document declaring entities; both now share one
guard. Scrapers reach it through a single path bootstrap in the
package rather than two ad-hoc ones.

scripts/scraper/targets/batocera_targets_scraper.py

@@ -19,6 +19,8 @@ from datetime import datetime, timezone
 
 import yaml
 
+from common import yaml_load
+
 from . import BaseTargetScraper
 
 PLATFORM_NAME = "batocera"
@@ -221,7 +223,7 @@ def _parse_es_systems(text: str) -> dict[str, list[str]]:
           <core_name>: {requireAnyOf: [BR2_PACKAGE_FOO]}
     """
     try:
-        data = yaml.safe_load(text)
+        data = yaml_load(text)
     except yaml.YAMLError:
         return {}
 

scripts/scraper/targets/emudeck_targets_scraper.py

@@ -17,6 +17,8 @@ from datetime import datetime, timezone
 
 import yaml
 
+from common import yaml_load
+
 from . import BaseTargetScraper
 
 PLATFORM_NAME = "emudeck"
@@ -134,7 +136,7 @@ class Scraper(BaseTargetScraper):
         if not os.path.exists(target_path):
             return []
         with open(target_path) as f:
-            data = yaml.safe_load(f) or {}
+            data = yaml_load(f) or {}
         # Find a target matching the architecture
         for tname, tinfo in data.get("targets", {}).items():
             if tinfo.get("architecture") == arch: