test(tools): add unit tests for error handling functions

* Implement tests for error functions like errRequiredField, errInvalidField, and errEntityNotFound.
* Ensure proper metadata is returned for various error scenarios.
* Validate error handling in CRM, Files, and other tools.
* Introduce tests for parsing stored file IDs and UUIDs.
* Enhance coverage for helper functions related to project resolution and session management.

internal/ai/compat/client.go

@@ -493,7 +493,7 @@ func (c *Client) doJSON(ctx context.Context, path string, requestBody any, dest
 		}
 
 		payload, readErr := io.ReadAll(resp.Body)
-		resp.Body.Close()
+		_ = resp.Body.Close()
 		if readErr != nil {
 			lastErr = fmt.Errorf("%s read response: %w", c.name, readErr)
 			if attempt < maxAttempts {
@@ -587,7 +587,9 @@ func (c *Client) doChatCompletions(ctx context.Context, reqBody chatCompletionsR
 }
 
 func (c *Client) decodeChatCompletionsResponse(resp *http.Response) (chatCompletionsResponse, error) {
-	defer resp.Body.Close()
+	defer func() {
+		_ = resp.Body.Close()
+	}()
 
 	contentType := strings.ToLower(resp.Header.Get("Content-Type"))
 	if strings.Contains(contentType, "text/event-stream") {

internal/ai/compat/client_test.go

@@ -15,7 +15,9 @@ func TestExtractMetadataFromStreamingResponse(t *testing.T) {
 	t.Parallel()
 
 	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		defer r.Body.Close()
+		defer func() {
+			_ = r.Body.Close()
+		}()
 
 		var req chatCompletionsRequest
 		if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
@@ -68,7 +70,9 @@ func TestExtractMetadataRetriesWithoutJSONMode(t *testing.T) {
 	plainCalls := 0
 
 	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		defer r.Body.Close()
+		defer func() {
+			_ = r.Body.Close()
+		}()
 
 		var req chatCompletionsRequest
 		if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
@@ -131,7 +135,9 @@ func TestExtractMetadataBypassesInvalidFallbackModelAfterFirstFailure(t *testing
 	invalidFallbackCalls := 0
 
 	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		defer r.Body.Close()
+		defer func() {
+			_ = r.Body.Close()
+		}()
 
 		var req chatCompletionsRequest
 		if err := json.NewDecoder(r.Body).Decode(&req); err != nil {