chore: add OpenCode configuration

Signed-off-by: Jérôme Benoit <jerome.benoit@piment-noir.org>

Author: jerome-benoit

.opencode/opencode.jsonc

@@ -0,0 +1,11 @@
+{
+  "$schema": "https://opencode.ai/config.json",
+  "formatter": {
+    "prettier": {
+      "disabled": true
+    },
+    "biome": {
+      "disabled": true
+    }
+  }
+}