fix: golangci-lint issues (unused helpers, empty branch, errcheck, gofmt)

backend/internal/pkg/apicompat/chatcompletions_anthropic_bridge.go

@@ -362,10 +362,8 @@ func ChatCompletionsResponseToAnthropic(resp *ChatCompletionsResponse, model str
 			choice := resp.Choices[0]
 			out.Content = chatMessageToAnthropicBlocks(choice.Message)
 			out.StopReason = chatFinishReasonToAnthropicStopReason(choice.FinishReason, out.Content)
-			if choice.FinishReason == "length" {
-				// Anthropic conveys max-tokens via stop_reason only; no separate
-				// incomplete_details field. stop_sequence stays nil.
-			}
+			// "length" → "max_tokens" is handled by chatFinishReasonToAnthropicStopReason;
+			// Anthropic conveys max-tokens via stop_reason only, no incomplete_details field.
 		}
 		if resp.Usage != nil {
 			out.Usage = chatUsageToAnthropicUsage(resp.Usage)
@@ -483,13 +481,13 @@ type ChatCompletionsToAnthropicStreamState struct {
 	MessageStopSent  bool
 
 	// Current content block lifecycle.
-	ContentBlockIndex int
-	ContentBlockOpen  bool
-	CurrentBlockType  string // "text" | "thinking" | "tool_use"
-	CurrentToolName   string
-	CurrentToolArgs   string
+	ContentBlockIndex   int
+	ContentBlockOpen    bool
+	CurrentBlockType    string // "text" | "thinking" | "tool_use"
+	CurrentToolName     string
+	CurrentToolArgs     string
 	CurrentToolHadDelta bool
-	HasToolCall        bool
+	HasToolCall         bool
 
 	// Tool calls keyed by the upstream tool_call index. The Anthropic block
 	// index assigned at content_block_start time is stored so later argument
@@ -519,9 +517,9 @@ type ChatCompletionsToAnthropicStreamState struct {
 // NewChatCompletionsToAnthropicStreamState returns an initialized stream state.
 func NewChatCompletionsToAnthropicStreamState(model string) *ChatCompletionsToAnthropicStreamState {
 	return &ChatCompletionsToAnthropicStreamState{
-		ResponseID:     generateResponsesID(),
-		Model:          model,
-		Created:        time.Now().Unix(),
+		ResponseID:        generateResponsesID(),
+		Model:             model,
+		Created:           time.Now().Unix(),
 		toolBlockIndex:    make(map[int]int),
 		toolAnnounced:     make(map[int]bool),
 		toolName:          make(map[int]string),

backend/internal/pkg/apicompat/chatcompletions_anthropic_bridge_test.go

@@ -12,9 +12,6 @@ import (
 // Helpers
 // ---------------------------------------------------------------------------
 
-func strPtr(s string) *string { return &s }
-func intPtr(v int) *int       { return &v }
-
 // collectAnthropicStreamEvents feeds CC chunks through the direct bridge and
 // appends finalize events, returning the full Anthropic event sequence.
 func collectAnthropicStreamEvents(t *testing.T, chunks []string) []AnthropicStreamEvent {
@@ -199,7 +196,8 @@ func TestAnthropicToChatCompletionsRequest_ToolChoiceSpecificTool(t *testing.T)
 	var tc map[string]any
 	require.NoError(t, json.Unmarshal(out.ToolChoice, &tc))
 	require.Equal(t, "function", tc["type"])
-	fn := tc["function"].(map[string]any)
+	fn, ok := tc["function"].(map[string]any)
+	require.True(t, ok, "tool_choice function should be a map")
 	require.Equal(t, "get_weather", fn["name"])
 }
 
@@ -254,10 +252,10 @@ func TestAnthropicToChatCompletionsRequest_MaxTokensFloor(t *testing.T) {
 
 func TestAnthropicToChatCompletionsRequest_ReasoningEffortMapping(t *testing.T) {
 	req := &AnthropicRequest{
-		Model:         "gpt-5.4",
-		MaxTokens:     100,
-		OutputConfig:  &AnthropicOutputConfig{Effort: "max"},
-		Messages:      []AnthropicMessage{{Role: "user", Content: json.RawMessage(`"hi"`)}},
+		Model:        "gpt-5.4",
+		MaxTokens:    100,
+		OutputConfig: &AnthropicOutputConfig{Effort: "max"},
+		Messages:     []AnthropicMessage{{Role: "user", Content: json.RawMessage(`"hi"`)}},
 	}
 
 	out, err := AnthropicToChatCompletionsRequest(req)