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/runner_test.go

@@ -0,0 +1,139 @@
+package ai
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"sync"
+	"testing"
+
+	"git.warky.dev/wdevs/amcs/internal/config"
+)
+
+func TestEmbeddingRunnerFallsBackAndSkipsUnhealthyPrimary(t *testing.T) {
+	var (
+		mu           sync.Mutex
+		primaryCalls int
+	)
+
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path != "/embeddings" {
+			http.NotFound(w, r)
+			return
+		}
+		var req struct {
+			Model string `json:"model"`
+		}
+		if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+			http.Error(w, err.Error(), http.StatusBadRequest)
+			return
+		}
+		switch req.Model {
+		case "embed-primary":
+			mu.Lock()
+			primaryCalls++
+			mu.Unlock()
+			http.Error(w, "upstream down", http.StatusBadGateway)
+		case "embed-fallback":
+			_ = json.NewEncoder(w).Encode(map[string]any{
+				"data": []map[string]any{{"embedding": []float32{0.1, 0.2, 0.3}}},
+			})
+		default:
+			http.Error(w, "unknown model", http.StatusBadRequest)
+		}
+	}))
+	defer srv.Close()
+
+	reg, err := NewRegistry(map[string]config.ProviderConfig{
+		"p1": {Type: "litellm", BaseURL: srv.URL, APIKey: "k1"},
+		"p2": {Type: "litellm", BaseURL: srv.URL, APIKey: "k2"},
+	}, srv.Client(), nil)
+	if err != nil {
+		t.Fatalf("NewRegistry() error = %v", err)
+	}
+
+	runner, err := NewEmbeddingRunner(reg, []config.RoleTarget{
+		{Provider: "p1", Model: "embed-primary"},
+		{Provider: "p2", Model: "embed-fallback"},
+	}, 3, nil)
+	if err != nil {
+		t.Fatalf("NewEmbeddingRunner() error = %v", err)
+	}
+
+	res, err := runner.Embed(context.Background(), "hello")
+	if err != nil {
+		t.Fatalf("Embed() first call error = %v", err)
+	}
+	if res.Provider != "p2" || res.Model != "embed-fallback" {
+		t.Fatalf("Embed() first call target = %s/%s, want p2/embed-fallback", res.Provider, res.Model)
+	}
+
+	res, err = runner.Embed(context.Background(), "hello again")
+	if err != nil {
+		t.Fatalf("Embed() second call error = %v", err)
+	}
+	if res.Provider != "p2" || res.Model != "embed-fallback" {
+		t.Fatalf("Embed() second call target = %s/%s, want p2/embed-fallback", res.Provider, res.Model)
+	}
+
+	mu.Lock()
+	calls := primaryCalls
+	mu.Unlock()
+	if calls != 3 {
+		t.Fatalf("primary calls = %d, want 3 (first request retries 3x; second call should skip unhealthy primary)", calls)
+	}
+}
+
+func TestMetadataRunnerSummarizeFallsBack(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path != "/chat/completions" {
+			http.NotFound(w, r)
+			return
+		}
+		var req struct {
+			Model string `json:"model"`
+		}
+		if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+			http.Error(w, err.Error(), http.StatusBadRequest)
+			return
+		}
+		switch req.Model {
+		case "sum-primary":
+			http.Error(w, "provider error", http.StatusBadGateway)
+		case "sum-fallback":
+			_ = json.NewEncoder(w).Encode(map[string]any{
+				"choices": []map[string]any{{
+					"message": map[string]any{"role": "assistant", "content": "fallback summary"},
+				}},
+			})
+		default:
+			http.Error(w, "unknown model", http.StatusBadRequest)
+		}
+	}))
+	defer srv.Close()
+
+	reg, err := NewRegistry(map[string]config.ProviderConfig{
+		"p1": {Type: "litellm", BaseURL: srv.URL, APIKey: "k1"},
+		"p2": {Type: "litellm", BaseURL: srv.URL, APIKey: "k2"},
+	}, srv.Client(), nil)
+	if err != nil {
+		t.Fatalf("NewRegistry() error = %v", err)
+	}
+
+	runner, err := NewMetadataRunner(reg, []config.RoleTarget{
+		{Provider: "p1", Model: "sum-primary"},
+		{Provider: "p2", Model: "sum-fallback"},
+	}, 0.1, false, nil)
+	if err != nil {
+		t.Fatalf("NewMetadataRunner() error = %v", err)
+	}
+
+	summary, err := runner.Summarize(context.Background(), "system", "user")
+	if err != nil {
+		t.Fatalf("Summarize() error = %v", err)
+	}
+	if summary != "fallback summary" {
+		t.Fatalf("summary = %q, want %q", summary, "fallback summary")
+	}
+}