feat: Claude AI configuration supports custom base URL (#2249)

Because I am on an internal network, I need to use a proxy server to
access Claude's services. However, Wave currently does not provide the
ability to configure the base URL, so I have added this feature in hopes
of being able to use it.

---------

Co-authored-by: sawka <[email protected]>

Author: L1l1thLY

pkg/waveai/anthropicbackend.go

@@ -170,7 +170,13 @@ func (AnthropicBackend) StreamCompletion(ctx context.Context, request wshrpc.Wav
 			return
 		}
 
-		req, err := http.NewRequestWithContext(ctx, "POST", "https://api.anthropic.com/v1/messages", strings.NewReader(string(reqBody)))
+		// Build endpoint allowing custom base URL from presets/settings
+		endpoint := "https://api.anthropic.com/v1/messages"
+		if request.Opts.BaseURL != "" {
+			endpoint = strings.TrimSpace(request.Opts.BaseURL)
+		}
+
+		req, err := http.NewRequestWithContext(ctx, "POST", endpoint, strings.NewReader(string(reqBody)))
 		if err != nil {
 			rtn <- makeAIError(fmt.Errorf("failed to create anthropic request: %v", err))
 			return
@@ -179,7 +185,11 @@ func (AnthropicBackend) StreamCompletion(ctx context.Context, request wshrpc.Wav
 		req.Header.Set("Content-Type", "application/json")
 		req.Header.Set("Accept", "text/event-stream")
 		req.Header.Set("x-api-key", request.Opts.APIToken)
-		req.Header.Set("anthropic-version", "2023-06-01")
+		version := "2023-06-01"
+		if request.Opts.APIVersion != "" {
+			version = request.Opts.APIVersion
+		}
+		req.Header.Set("anthropic-version", version)
 
 		// Configure HTTP client with proxy if specified
 		client := &http.Client{}

pkg/waveai/googlebackend.go

@@ -20,7 +20,7 @@ var _ AIBackend = GoogleBackend{}
 func (GoogleBackend) StreamCompletion(ctx context.Context, request wshrpc.WaveAIStreamRequest) chan wshrpc.RespOrErrorUnion[wshrpc.WaveAIPacketType] {
 	var clientOptions []option.ClientOption
 	clientOptions = append(clientOptions, option.WithAPIKey(request.Opts.APIToken))
-	
+
 	// Configure proxy if specified
 	if request.Opts.ProxyURL != "" {
 		proxyURL, err := url.Parse(request.Opts.ProxyURL)
@@ -65,11 +65,9 @@ func (GoogleBackend) StreamCompletion(ctx context.Context, request wshrpc.WaveAI
 		defer close(rtn)
 		for {
 			// Check for context cancellation
-			select {
-			case <-ctx.Done():
-				rtn <- makeAIError(fmt.Errorf("request cancelled: %v", ctx.Err()))
+			if err := ctx.Err(); err != nil {
+				rtn <- makeAIError(fmt.Errorf("request cancelled: %v", err))
 				break
-			default:
 			}
 
 			resp, err := iter.Next()