test(config): add migration tests for litellm provider

* Implement tests for migrating configuration from v1 to v2 for the litellm provider.
* Validate the structure and values of the migrated configuration.
* Ensure migration rejects newer versions of the configuration.
fix(validate): enhance AI provider validation logic
* Consolidate provider validation into a dedicated method.
* Ensure at least one provider is specified and validate its type.
* Check for required fields based on provider type.
fix(mcpserver): update tool set to use new enrichment tool
* Replace RetryMetadataTool with RetryEnrichmentTool in the ToolSet.
fix(tools): refactor tools to use embedding and metadata runners
* Update tools to utilize EmbeddingRunner and MetadataRunner instead of Provider.
* Adjust method calls to align with the new runner interfaces.

internal/ai/registry_test.go

@@ -0,0 +1,80 @@
+package ai
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"git.warky.dev/wdevs/amcs/internal/ai/compat"
+	"git.warky.dev/wdevs/amcs/internal/config"
+)
+
+func TestNewRegistryOpenRouterHeaders(t *testing.T) {
+	var (
+		gotReferer string
+		gotTitle   string
+		gotCustom  string
+	)
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		gotReferer = r.Header.Get("HTTP-Referer")
+		gotTitle = r.Header.Get("X-Title")
+		gotCustom = r.Header.Get("X-Custom")
+		_ = json.NewEncoder(w).Encode(map[string]any{
+			"choices": []map[string]any{{"message": map[string]any{"role": "assistant", "content": "ok"}}},
+		})
+	}))
+	defer srv.Close()
+
+	providers := map[string]config.ProviderConfig{
+		"router": {
+			Type:    "openrouter",
+			BaseURL: srv.URL,
+			APIKey:  "secret",
+			RequestHeaders: map[string]string{
+				"X-Custom": "value",
+			},
+			AppName: "amcs",
+			SiteURL: "https://example.com",
+		},
+	}
+
+	reg, err := NewRegistry(providers, srv.Client(), nil)
+	if err != nil {
+		t.Fatalf("NewRegistry() error = %v", err)
+	}
+
+	client, err := reg.Client("router")
+	if err != nil {
+		t.Fatalf("Client(router) error = %v", err)
+	}
+
+	if _, err := client.SummarizeWith(context.Background(), compat.SummarizeOptions{Model: "gpt-4.1-mini"}, "system", "user"); err != nil {
+		t.Fatalf("SummarizeWith() error = %v", err)
+	}
+	if gotReferer != "https://example.com" {
+		t.Fatalf("HTTP-Referer = %q, want https://example.com", gotReferer)
+	}
+	if gotTitle != "amcs" {
+		t.Fatalf("X-Title = %q, want amcs", gotTitle)
+	}
+	if gotCustom != "value" {
+		t.Fatalf("X-Custom = %q, want value", gotCustom)
+	}
+}
+
+func TestNewRegistryRejectsUnsupportedProviderType(t *testing.T) {
+	providers := map[string]config.ProviderConfig{
+		"bad": {
+			Type:    "unknown",
+			BaseURL: "http://localhost:4000/v1",
+			APIKey:  "secret",
+		},
+	}
+
+	_, err := NewRegistry(providers, &http.Client{}, nil)
+	if err == nil {
+		t.Fatal("NewRegistry() error = nil, want unsupported provider type error")
+	}
+}