refactor(watcher): extract config diff helpers

Break out config diffing, hashing, and OpenAI compatibility utilities into a dedicated diff package, update watcher to consume them, and add comprehensive tests for diff logic and watcher behavior.

internal/watcher/diff/oauth_excluded_test.go

@@ -0,0 +1,109 @@
+package diff
+
+import (
+	"testing"
+
+	"github.com/router-for-me/CLIProxyAPI/v6/internal/config"
+)
+
+func TestSummarizeExcludedModels_NormalizesAndDedupes(t *testing.T) {
+	summary := SummarizeExcludedModels([]string{"A", " a ", "B", "b"})
+	if summary.count != 2 {
+		t.Fatalf("expected 2 unique entries, got %d", summary.count)
+	}
+	if summary.hash == "" {
+		t.Fatal("expected non-empty hash")
+	}
+	if empty := SummarizeExcludedModels(nil); empty.count != 0 || empty.hash != "" {
+		t.Fatalf("expected empty summary for nil input, got %+v", empty)
+	}
+}
+
+func TestDiffOAuthExcludedModelChanges(t *testing.T) {
+	oldMap := map[string][]string{
+		"ProviderA": {"model-1", "model-2"},
+		"providerB": {"x"},
+	}
+	newMap := map[string][]string{
+		"providerA": {"model-1", "model-3"},
+		"providerC": {"y"},
+	}
+
+	changes, affected := DiffOAuthExcludedModelChanges(oldMap, newMap)
+	expectContains(t, changes, "oauth-excluded-models[providera]: updated (2 -> 2 entries)")
+	expectContains(t, changes, "oauth-excluded-models[providerb]: removed")
+	expectContains(t, changes, "oauth-excluded-models[providerc]: added (1 entries)")
+
+	if len(affected) != 3 {
+		t.Fatalf("expected 3 affected providers, got %d", len(affected))
+	}
+}
+
+func TestSummarizeAmpModelMappings(t *testing.T) {
+	summary := SummarizeAmpModelMappings([]config.AmpModelMapping{
+		{From: "a", To: "A"},
+		{From: "b", To: "B"},
+		{From: " ", To: " "}, // ignored
+	})
+	if summary.count != 2 {
+		t.Fatalf("expected 2 entries, got %d", summary.count)
+	}
+	if summary.hash == "" {
+		t.Fatal("expected non-empty hash")
+	}
+	if empty := SummarizeAmpModelMappings(nil); empty.count != 0 || empty.hash != "" {
+		t.Fatalf("expected empty summary for nil input, got %+v", empty)
+	}
+	if blank := SummarizeAmpModelMappings([]config.AmpModelMapping{{From: " ", To: " "}}); blank.count != 0 || blank.hash != "" {
+		t.Fatalf("expected blank mappings ignored, got %+v", blank)
+	}
+}
+
+func TestSummarizeOAuthExcludedModels_NormalizesKeys(t *testing.T) {
+	out := SummarizeOAuthExcludedModels(map[string][]string{
+		"ProvA": {"X"},
+		"":      {"ignored"},
+	})
+	if len(out) != 1 {
+		t.Fatalf("expected only non-empty key summary, got %d", len(out))
+	}
+	if _, ok := out["prova"]; !ok {
+		t.Fatalf("expected normalized key 'prova', got keys %v", out)
+	}
+	if out["prova"].count != 1 || out["prova"].hash == "" {
+		t.Fatalf("unexpected summary %+v", out["prova"])
+	}
+	if outEmpty := SummarizeOAuthExcludedModels(nil); outEmpty != nil {
+		t.Fatalf("expected nil map for nil input, got %v", outEmpty)
+	}
+}
+
+func TestSummarizeVertexModels(t *testing.T) {
+	summary := SummarizeVertexModels([]config.VertexCompatModel{
+		{Name: "m1"},
+		{Name: " ", Alias: "alias"},
+		{}, // ignored
+	})
+	if summary.count != 2 {
+		t.Fatalf("expected 2 vertex models, got %d", summary.count)
+	}
+	if summary.hash == "" {
+		t.Fatal("expected non-empty hash")
+	}
+	if empty := SummarizeVertexModels(nil); empty.count != 0 || empty.hash != "" {
+		t.Fatalf("expected empty summary for nil input, got %+v", empty)
+	}
+	if blank := SummarizeVertexModels([]config.VertexCompatModel{{Name: " "}}); blank.count != 0 || blank.hash != "" {
+		t.Fatalf("expected blank model ignored, got %+v", blank)
+	}
+}
+
+func expectContains(t *testing.T, list []string, target string) {
+	t.Helper()
+	for _, entry := range list {
+		if entry == target {
+			return
+		}
+	}
+	t.Fatalf("expected list to contain %q, got %#v", target, list)
+}