Centralize proxy HTTP client creation in aiutil and remove redundant backend tests (#2961)

`makeHTTPClient(proxyURL)` had been duplicated across AI backends with
equivalent behavior. This change consolidates the logic into a single
helper in `aiutil` and updates backends to consume it, then removes
backend-local tests that only re-verified that shared utility behavior.

- **Shared client construction**
- Added `aiutil.MakeHTTPClient(proxyURL string) (*http.Client, error)`
in `pkg/aiusechat/aiutil/aiutil.go`.
- Standardizes proxy parsing and `http.Transport.Proxy` setup in one
place.
- Keeps streaming-safe client semantics (`Timeout: 0`) and existing
invalid proxy URL error behavior.

- **Backend refactor**
  - Removed duplicated client/proxy setup blocks from:
    - `pkg/aiusechat/openaichat/openaichat-backend.go`
    - `pkg/aiusechat/gemini/gemini-backend.go`
    - `pkg/aiusechat/openai/openai-backend.go`
    - `pkg/aiusechat/anthropic/anthropic-backend.go`
  - Replaced with direct calls to the shared helper.

- **Test cleanup**
- Deleted backend tests that only covered basic proxy client creation
and no backend-specific behavior:
    - `pkg/aiusechat/openaichat/openaichat-backend_test.go`
    - `pkg/aiusechat/gemini/gemini-backend_test.go`

```go
httpClient, err := aiutil.MakeHTTPClient(chatOpts.Config.ProxyURL)
if err != nil {
    return nil, nil, nil, err
}
resp, err := httpClient.Do(req)
```

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package-lock.json

@@ -11,6 +11,8 @@ import (
 	"encoding/hex"
 	"encoding/json"
 	"fmt"
+	"net/http"
+	"net/url"
 	"strconv"
 	"strings"
 	"time"
@@ -185,6 +187,24 @@ func JsonEncodeRequestBody(reqBody any) (bytes.Buffer, error) {
 	return buf, nil
 }
 
+func MakeHTTPClient(proxyURL string) (*http.Client, error) {
+	client := &http.Client{
+		Timeout: 0, // rely on ctx; streaming can be long
+	}
+	if proxyURL == "" {
+		return client, nil
+	}
+
+	pURL, err := url.Parse(proxyURL)
+	if err != nil {
+		return nil, fmt.Errorf("invalid proxy URL: %w", err)
+	}
+	client.Transport = &http.Transport{
+		Proxy: http.ProxyURL(pURL),
+	}
+	return client, nil
+}
+
 func IsOpenAIReasoningModel(model string) bool {
 	m := strings.ToLower(model)
 	return CheckModelPrefix(m, "o1") ||

pkg/aiusechat/aiutil/aiutil.go

@@ -12,12 +12,12 @@ import (
 	"io"
 	"log"
 	"net/http"
-	"net/url"
 	"strings"
 	"time"
 
 	"github.com/google/uuid"
 	"github.com/launchdarkly/eventsource"
+	"github.com/wavetermdev/waveterm/pkg/aiusechat/aiutil"
 	"github.com/wavetermdev/waveterm/pkg/aiusechat/chatstore"
 	"github.com/wavetermdev/waveterm/pkg/aiusechat/uctypes"
 	"github.com/wavetermdev/waveterm/pkg/util/utilfn"
@@ -454,18 +454,9 @@ func RunAnthropicChatStep(
 		return nil, nil, nil, err
 	}
 
-	httpClient := &http.Client{
-		Timeout: 0, // rely on ctx; streaming can be long
-	}
-	// Proxy support
-	if chatOpts.Config.ProxyURL != "" {
-		pURL, perr := url.Parse(chatOpts.Config.ProxyURL)
-		if perr != nil {
-			return nil, nil, nil, fmt.Errorf("invalid proxy URL: %w", perr)
-		}
-		httpClient.Transport = &http.Transport{
-			Proxy: http.ProxyURL(pURL),
-		}
+	httpClient, err := aiutil.MakeHTTPClient(chatOpts.Config.ProxyURL)
+	if err != nil {
+		return nil, nil, nil, err
 	}
 
 	resp, err := httpClient.Do(req)

pkg/aiusechat/anthropic/anthropic-backend.go

@@ -231,8 +231,9 @@ func RunGeminiChatStep(
 		return nil, nil, nil, err
 	}
 
-	httpClient := &http.Client{
-		Timeout: 0, // rely on ctx; streaming can be long
+	httpClient, err := aiutil.MakeHTTPClient(chatOpts.Config.ProxyURL)
+	if err != nil {
+		return nil, nil, nil, err
 	}
 
 	resp, err := httpClient.Do(req)

pkg/aiusechat/gemini/gemini-backend.go

@@ -528,18 +528,9 @@ func RunOpenAIChatStep(
 		return nil, nil, nil, err
 	}
 
-	httpClient := &http.Client{
-		Timeout: 0, // rely on ctx; streaming can be long
-	}
-	// Proxy support
-	if chatOpts.Config.ProxyURL != "" {
-		pURL, perr := url.Parse(chatOpts.Config.ProxyURL)
-		if perr != nil {
-			return nil, nil, nil, fmt.Errorf("invalid proxy URL: %w", perr)
-		}
-		httpClient.Transport = &http.Transport{
-			Proxy: http.ProxyURL(pURL),
-		}
+	httpClient, err := aiutil.MakeHTTPClient(chatOpts.Config.ProxyURL)
+	if err != nil {
+		return nil, nil, nil, err
 	}
 
 	resp, err := httpClient.Do(req)

pkg/aiusechat/openai/openai-backend.go

@@ -16,6 +16,7 @@ import (
 
 	"github.com/google/uuid"
 	"github.com/launchdarkly/eventsource"
+	"github.com/wavetermdev/waveterm/pkg/aiusechat/aiutil"
 	"github.com/wavetermdev/waveterm/pkg/aiusechat/chatstore"
 	"github.com/wavetermdev/waveterm/pkg/aiusechat/uctypes"
 	"github.com/wavetermdev/waveterm/pkg/web/sse"
@@ -60,7 +61,10 @@ func RunChatStep(
 		return nil, nil, nil, err
 	}
 
-	client := &http.Client{}
+	client, err := aiutil.MakeHTTPClient(chatOpts.Config.ProxyURL)
+	if err != nil {
+		return nil, nil, nil, err
+	}
 	resp, err := client.Do(req)
 	if err != nil {
 		return nil, nil, nil, fmt.Errorf("request failed: %w", err)

pkg/aiusechat/openaichat/openaichat-backend.go

@@ -189,29 +189,6 @@ const (
 	ApprovalCanceled      = "canceled"
 )
 
-type AIModeConfig struct {
-	Mode               string   `json:"mode"`
-	DisplayName        string   `json:"display:name"`
-	DisplayOrder       float64  `json:"display:order,omitempty"`
-	DisplayIcon        string   `json:"display:icon"`
-	Provider           string   `json:"provider,omitempty"`
-	APIType            string   `json:"apitype"`
-	Model              string   `json:"model"`
-	ThinkingLevel      string   `json:"thinkinglevel"`
-	BaseURL            string   `json:"baseurl,omitempty"`
-	WaveAICloud        bool     `json:"waveaicloud,omitempty"`
-	APIVersion         string   `json:"apiversion,omitempty"`
-	APIToken           string   `json:"apitoken,omitempty"`
-	APITokenSecretName string   `json:"apitokensecretname,omitempty"`
-	Premium            bool     `json:"premium"`
-	Description        string   `json:"description"`
-	Capabilities       []string `json:"capabilities,omitempty"`
-}
-
-func (c *AIModeConfig) HasCapability(cap string) bool {
-	return slices.Contains(c.Capabilities, cap)
-}
-
 // when updating this struct, also modify frontend/app/aipanel/aitypes.ts WaveUIDataTypes.tooluse
 type UIMessageDataToolUse struct {
 	ToolCallId          string `json:"toolcallid"`

pkg/aiusechat/uctypes/uctypes.go

@@ -123,6 +123,7 @@ func getWaveAISettings(premium bool, builderMode bool, rtInfo waveobj.ObjRTInfo,
 		Verbosity:     verbosity,
 		AIMode:        aiMode,
 		Endpoint:      baseUrl,
+		ProxyURL:      config.ProxyURL,
 		Capabilities:  config.Capabilities,
 		WaveAIPremium: config.WaveAIPremium,
 	}

pkg/aiusechat/usechat.go

@@ -25,3 +25,15 @@ func TestApplyProviderDefaultsGroq(t *testing.T) {
 		t.Fatalf("expected API token secret name %q, got %q", GroqAPITokenSecretName, config.APITokenSecretName)
 	}
 }
+
+func TestApplyProviderDefaultsKeepsProxyURL(t *testing.T) {
+	config := wconfig.AIModeConfigType{
+		Provider: uctypes.AIProvider_OpenAI,
+		Model:    "gpt-5-mini",
+		ProxyURL: "http://localhost:8080",
+	}
+	applyProviderDefaults(&config)
+	if config.ProxyURL != "http://localhost:8080" {
+		t.Fatalf("expected proxy URL to be preserved, got %q", config.ProxyURL)
+	}
+}

pkg/aiusechat/usechat_mode_test.go

@@ -288,6 +288,7 @@ type AIModeConfigType struct {
 	ThinkingLevel      string   `json:"ai:thinkinglevel,omitempty" jsonschema:"enum=low,enum=medium,enum=high"`
 	Verbosity          string   `json:"ai:verbosity,omitempty" jsonschema:"enum=low,enum=medium,enum=high,description=Text verbosity level (OpenAI Responses API only)"`
 	Endpoint           string   `json:"ai:endpoint,omitempty"`
+	ProxyURL           string   `json:"ai:proxyurl,omitempty"`
 	AzureAPIVersion    string   `json:"ai:azureapiversion,omitempty"`
 	APIToken           string   `json:"ai:apitoken,omitempty"`
 	APITokenSecretName string   `json:"ai:apitokensecretname,omitempty"`