feat(agent): refactor AI chat with streaming, agent registry, and tool execution

- Replace old tool-call regex with proper agent registry
- Add streaming chat via SSE (handleStreamChat / handleNonStreamChat)
- Add internal/agent package with tool definitions and execution
- Add orchestrator with system prompt and tool scaffolding
- Add internal/agent/ directory
- Studio.jsx: streaming chat with thinking indicator and tool result rendering
- global.css: chat bubble styles, streaming animation, thinking dots
- handlers_chat.go: full rewrite using new agent/orchestrator architecture

💘 Generated with Crush

Assisted-by: MiniMax-M2.7 via Crush <crush@charm.land>

internal/orchestrator/orchestrator.go

@@ -20,24 +20,42 @@ var thinkRegex = regexp.MustCompile(`(?s)<[Tt]hink[^>]*>.*?</[Tt]hink>`)
 const maxHistorySize = 100
 
 type Message struct {
-	Role    string `json:"role"`
-	Content string `json:"content"`
+	Role       string          `json:"role"`
+	Content    string          `json:"content,omitempty"`
+	ToolCalls  []ToolCallMsg   `json:"tool_calls,omitempty"`
+	ToolCallID string          `json:"tool_call_id,omitempty"`
+	Name       string          `json:"name,omitempty"`
+}
+
+type ToolCallMsg struct {
+	ID       string             `json:"id"`
+	Type     string             `json:"type"`
+	Function ToolCallFuncMsg    `json:"function"`
+}
+
+type ToolCallFuncMsg struct {
+	Name      string `json:"name"`
+	Arguments string `json:"arguments"`
 }
 
 type ChatRequest struct {
-	Model    string    `json:"model"`
-	Messages []Message `json:"messages"`
-	Stream   bool      `json:"stream"`
+	Model    string          `json:"model"`
+	Messages []Message       `json:"messages"`
+	Stream   bool            `json:"stream"`
+	Tools    json.RawMessage `json:"tools,omitempty"`
 }
 
 type ChatResponse struct {
 	Choices []struct {
 		Message struct {
-			Content string `json:"content"`
+			Content   string        `json:"content"`
+			ToolCalls []ToolCallMsg `json:"tool_calls"`
 		} `json:"message"`
 		Delta struct {
-			Content string `json:"content"`
+			Content   string        `json:"content"`
+			ToolCalls []ToolCallMsg `json:"tool_calls"`
 		} `json:"delta"`
+		FinishReason *string `json:"finish_reason"`
 	} `json:"choices"`
 	Usage struct {
 		TotalTokens int `json:"total_tokens"`
@@ -51,6 +69,7 @@ type Orchestrator struct {
 	history      []Message
 	histMu       sync.Mutex
 	systemPrompt string
+	tools        json.RawMessage
 }
 
 var sharedHTTPClient = &http.Client{
@@ -86,6 +105,34 @@ func (o *Orchestrator) SetSystemPrompt(prompt string) {
 	o.systemPrompt = prompt
 }
 
+func (o *Orchestrator) SetTools(tools json.RawMessage) {
+	o.tools = tools
+}
+
+func (o *Orchestrator) ProviderName() string {
+	if o.provider == nil {
+		return ""
+	}
+	return o.provider.Name
+}
+
+func (o *Orchestrator) AppendHistory(msg Message) {
+	o.histMu.Lock()
+	defer o.histMu.Unlock()
+	o.history = append(o.history, msg)
+	if len(o.history) > maxHistorySize {
+		o.history = o.history[len(o.history)-maxHistorySize:]
+	}
+}
+
+func (o *Orchestrator) GetHistory() []Message {
+	o.histMu.Lock()
+	defer o.histMu.Unlock()
+	out := make([]Message, len(o.history))
+	copy(out, o.history)
+	return out
+}
+
 func (o *Orchestrator) Send(userMessage string) (string, error) {
 	o.histMu.Lock()
 	o.history = append(o.history, Message{
@@ -107,6 +154,7 @@ func (o *Orchestrator) Send(userMessage string) (string, error) {
 		Model:    o.provider.Model,
 		Messages: messages,
 		Stream:   false,
+		Tools:    o.tools,
 	}
 	o.histMu.Unlock()
 
@@ -186,6 +234,7 @@ func (o *Orchestrator) SendStream(userMessage string, onChunk func(string)) (str
 		Model:    o.provider.Model,
 		Messages: messages,
 		Stream:   true,
+		Tools:    o.tools,
 	}
 	o.histMu.Unlock()
 
@@ -263,6 +312,67 @@ func (o *Orchestrator) SendStream(userMessage string, onChunk func(string)) (str
 	return content, nil
 }
 
+func (o *Orchestrator) SendWithTools(messages []Message) (*ChatResponse, error) {
+	fullMessages := make([]Message, 0, len(messages)+1)
+	if o.systemPrompt != "" {
+		fullMessages = append(fullMessages, Message{Role: "system", Content: o.systemPrompt})
+	}
+	fullMessages = append(fullMessages, messages...)
+
+	reqBody := ChatRequest{
+		Model:    o.provider.Model,
+		Messages: fullMessages,
+		Stream:   false,
+		Tools:    o.tools,
+	}
+
+	body, err := json.Marshal(reqBody)
+	if err != nil {
+		return nil, fmt.Errorf("marshal request: %w", err)
+	}
+
+	baseURL := o.provider.BaseURL
+	if baseURL == "" {
+		baseURL = getProviderBaseURL(o.provider.Name)
+	}
+
+	url := strings.TrimRight(baseURL, "/") + "/chat/completions"
+
+	req, err := http.NewRequest("POST", url, bytes.NewReader(body))
+	if err != nil {
+		return nil, fmt.Errorf("create request: %w", err)
+	}
+
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("Authorization", "Bearer "+o.provider.APIKey)
+
+	resp, err := o.client.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("send request: %w", err)
+	}
+	defer resp.Body.Close()
+
+	respBody, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, fmt.Errorf("read response: %w", err)
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("API error (%d): %s", resp.StatusCode, string(respBody))
+	}
+
+	var chatResp ChatResponse
+	if err := json.Unmarshal(respBody, &chatResp); err != nil {
+		return nil, fmt.Errorf("parse response: %w", err)
+	}
+
+	if len(chatResp.Choices) == 0 {
+		return nil, fmt.Errorf("no response from AI")
+	}
+
+	return &chatResp, nil
+}
+
 func cleanAIResponse(content string) string {
 	content = thinkRegex.ReplaceAllString(content, "")
 	lines := strings.Split(content, "\n")