feat(settings): implement provider-specific model lists

- Add PROVIDER_MODELS config with Anthropic, OpenRouter, and LiteLLM model mappings
- Update _get_available_models() to accept provider parameter
- Modal now loads models based on current provider setting
- Model dropdowns dynamically update when switching providers

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: joachimBrindeau

src/claude_code_proxy/api/routes/settings.py

@@ -14,7 +14,6 @@
     ModelProvider,
     get_model_resolution_settings,
 )
-from claude_code_proxy.services.model_resolver import get_model_resolver
 
 
 logger = get_logger(__name__)
@@ -25,6 +24,63 @@
 TEMPLATES_DIR = Path(__file__).parent.parent.parent / "ui" / "templates"
 jinja_env = Environment(loader=FileSystemLoader(str(TEMPLATES_DIR)), autoescape=True)
 
+# Provider-specific model configurations
+PROVIDER_MODELS: dict[str, dict[str, list[str]]] = {
+    "anthropic": {
+        "sonnet": [
+            "claude-sonnet-4-5-20250514",
+            "claude-sonnet-4-20250514",
+            "claude-3-5-sonnet-20241022",
+            "claude-3-5-sonnet-latest",
+        ],
+        "opus": [
+            "claude-opus-4-5-20250514",
+            "claude-opus-4-20250514",
+            "claude-3-opus-20240229",
+            "claude-3-opus-latest",
+        ],
+        "haiku": [
+            "claude-haiku-4-5-20250514",
+            "claude-3-5-haiku-20241022",
+            "claude-3-5-haiku-latest",
+        ],
+    },
+    "openrouter": {
+        "sonnet": [
+            "anthropic/claude-sonnet-4",
+            "anthropic/claude-3.5-sonnet",
+            "anthropic/claude-3.5-sonnet:beta",
+        ],
+        "opus": [
+            "anthropic/claude-opus-4",
+            "anthropic/claude-3-opus",
+            "anthropic/claude-3-opus:beta",
+        ],
+        "haiku": [
+            "anthropic/claude-3.5-haiku",
+            "anthropic/claude-3.5-haiku:beta",
+            "anthropic/claude-3-haiku",
+        ],
+    },
+    "litellm": {
+        "sonnet": [
+            "claude-sonnet-4-5-20250514",
+            "anthropic/claude-sonnet-4-5-20250514",
+            "claude-3-5-sonnet-latest",
+        ],
+        "opus": [
+            "claude-opus-4-5-20250514",
+            "anthropic/claude-opus-4-5-20250514",
+            "claude-3-opus-latest",
+        ],
+        "haiku": [
+            "claude-haiku-4-5-20250514",
+            "anthropic/claude-haiku-4-5-20250514",
+            "claude-3-5-haiku-latest",
+        ],
+    },
+}
+
 
 def _get_current_settings() -> dict[str, Any]:
     """Get current model resolution settings."""
@@ -49,26 +105,9 @@ def _get_current_settings() -> dict[str, Any]:
     }
 
 
-def _get_available_models() -> dict[str, list[str]]:
-    """Get available models by tier from the resolver."""
-    resolver = get_model_resolver()
-    if resolver:
-        tier_models = resolver.get_models_by_tier()
-        return {
-            "sonnet": tier_models.get("sonnet", ["claude-sonnet-4-5"]),
-            "opus": tier_models.get("opus", ["claude-opus-4-5"]),
-            "haiku": tier_models.get("haiku", ["claude-haiku-4-5"]),
-        }
-    # Fallback defaults
-    return {
-        "sonnet": [
-            "claude-sonnet-4-5",
-            "claude-sonnet-4",
-            "claude-3-5-sonnet-20241022",
-        ],
-        "opus": ["claude-opus-4-5", "claude-opus-4", "claude-3-opus-20240229"],
-        "haiku": ["claude-haiku-4-5", "claude-3-5-haiku-20241022"],
-    }
+def _get_available_models(provider: str = "anthropic") -> dict[str, list[str]]:
+    """Get available models by tier for the specified provider."""
+    return PROVIDER_MODELS.get(provider, PROVIDER_MODELS["anthropic"])
 
 
 @router.get("")
@@ -171,10 +210,11 @@ async def update_tier_defaults(
 async def settings_modal(request: Request) -> HTMLResponse:
     """Render the settings modal."""
     template = jinja_env.get_template("settings_modal.html")
+    settings = _get_current_settings()
 
     content = template.render(
-        settings=_get_current_settings(),
-        available_models=_get_available_models(),
+        settings=settings,
+        available_models=_get_available_models(settings["provider"]),
     )
 
     return HTMLResponse(content=content)
@@ -185,13 +225,11 @@ async def models_for_provider(
     request: Request, provider: str, tier: str
 ) -> HTMLResponse:
     """Return model options for a specific provider and tier."""
-    # TODO: Implement provider-specific model fetching
-    available_models = _get_available_models()
+    available_models = _get_available_models(provider)
     tier_models = available_models.get(tier, [])
-    current_settings = _get_current_settings()
-    current_default = current_settings["tier_defaults"].get(
-        tier, tier_models[0] if tier_models else ""
-    )
+
+    # Use first model as default for new provider
+    current_default = tier_models[0] if tier_models else ""
 
     template = jinja_env.get_template("partials/model_select.html")
     return HTMLResponse(