refactor: moved registries into a separate module and code cleanup

fix: refactored dial provider to follow the same pattern

providers/registries/gemini.py

@@ -0,0 +1,19 @@
+"""Registry loader for Gemini model capabilities."""
+
+from __future__ import annotations
+
+from ..shared import ProviderType
+from .base import CapabilityModelRegistry
+
+
+class GeminiModelRegistry(CapabilityModelRegistry):
+    """Capability registry backed by ``conf/gemini_models.json``."""
+
+    def __init__(self, config_path: str | None = None) -> None:
+        super().__init__(
+            env_var_name="GEMINI_MODELS_CONFIG_PATH",
+            default_filename="gemini_models.json",
+            provider=ProviderType.GOOGLE,
+            friendly_prefix="Gemini ({model})",
+            config_path=config_path,
+        )