feat: 添加 VEO3 场景写作和角色定义 SDK

- 新增 gemini-sdk: 基于 Gemini AI 的通用 SDK
- 新增 veo3-scene-writer: VEO3 场景写作专用工具
  - 支持图片/视频附件分析
  - 多轮会话功能
  - VEO3 专业提示词集成
  - 角色一致性管理
- 新增 Veo3ActorDefine: 角色定义专用工具
- 添加完整的示例和文档
- 支持多种输出格式 (文本/JSON/YAML)

cargos/gemini-sdk/README.md

@@ -0,0 +1,189 @@
+# Gemini SDK
+
+A simple and powerful Rust SDK for Google Gemini AI services.
+
+## Features
+
+- **Simple Interface**: Send text + attachments to Gemini AI
+- **Agent System**: Create specialized AI agents with custom system prompts and configurations
+- **Type Safety**: Strong typing with compile-time error checking
+- **Easy Integration**: Minimal external dependencies
+
+## Quick Start
+
+Add this to your `Cargo.toml`:
+
+```toml
+[dependencies]
+gemini-sdk = { path = "../gemini-sdk" }
+tokio = { version = "1.0", features = ["full"] }
+```
+
+### Basic Usage
+
+```rust
+use gemini_sdk::{GeminiSDK, MessageRequest, Agent};
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    // Initialize SDK
+    let mut sdk = GeminiSDK::new()?;
+
+    // Simple text message
+    let request = MessageRequest::text_only("Hello, how are you?");
+    let response = sdk.send_message(request).await?;
+    println!("Response: {}", response.content);
+
+    Ok(())
+}
+```
+
+### Using Agents
+
+```rust
+use gemini_sdk::{GeminiSDK, MessageRequest, Agent};
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let mut sdk = GeminiSDK::new()?;
+
+    // Create a specialized agent
+    let agent = Agent::new(
+        "code_reviewer",
+        "Code Reviewer",
+        "You are an expert code reviewer. Analyze code for bugs, suggest improvements, and provide constructive feedback."
+    ).with_temperature(0.3)  // Lower temperature for more focused responses
+     .with_max_tokens(4096);
+
+    sdk.add_agent(agent);
+
+    // Use the agent
+    let request = MessageRequest::with_agent(
+        "Please review this Python code: def fibonacci(n): return n if n <= 1 else fibonacci(n-1) + fibonacci(n-2)",
+        "code_reviewer"
+    );
+
+    let response = sdk.send_message(request).await?;
+    println!("Code review: {}", response.content);
+
+    Ok(())
+}
+```
+
+### With Image Attachments
+
+```rust
+use gemini_sdk::{GeminiSDK, MessageRequest, Attachment};
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let mut sdk = GeminiSDK::new()?;
+
+    let request = MessageRequest::with_attachments(
+        "What do you see in this image?",
+        vec![Attachment::new("./image.jpg")]
+    );
+
+    let response = sdk.send_message(request).await?;
+    println!("Image analysis: {}", response.content);
+
+    Ok(())
+}
+```
+
+## Configuration
+
+The SDK uses environment variables for configuration, with sensible defaults:
+
+- `GEMINI_BASE_URL`: API base URL (default: Bowong AI endpoint)
+- `GEMINI_BEARER_TOKEN`: Bearer token for authentication (default: "bowong7777")
+- `GEMINI_MODEL_NAME`: Model to use (default: "gemini-2.5-flash")
+- `GEMINI_TEMPERATURE`: Default temperature (default: 0.7)
+- `GEMINI_MAX_TOKENS`: Default max tokens (default: 64000)
+
+You can also create a custom configuration:
+
+```rust
+use gemini_sdk::{GeminiSDK, GeminiConfig};
+
+let config = GeminiConfig {
+    base_url: "https://your-api-endpoint.com".to_string(),
+    bearer_token: "your-token".to_string(),
+    model_name: "gemini-2.5-flash".to_string(),
+    temperature: 0.8,
+    max_tokens: 32000,
+    ..Default::default()
+};
+
+let mut sdk = GeminiSDK::with_config(config)?;
+```
+
+## Agent System
+
+Agents are specialized AI assistants with their own system prompts and configurations:
+
+```rust
+// Create an agent
+let agent = Agent::new("agent_id", "Agent Name", "System prompt here")
+    .with_temperature(0.5)    // 0.0 = focused, 2.0 = creative
+    .with_max_tokens(8192);   // Maximum response length
+
+// Add to SDK
+sdk.add_agent(agent);
+
+// Use the agent
+let request = MessageRequest::with_agent("Your message", "agent_id");
+let response = sdk.send_message(request).await?;
+```
+
+### Agent Management
+
+```rust
+// List all agents
+let agents = sdk.list_agents();
+for agent in agents {
+    println!("Agent: {} ({})", agent.name, agent.id);
+}
+
+// Get specific agent
+if let Some(agent) = sdk.get_agent("agent_id") {
+    println!("Found agent: {}", agent.name);
+}
+
+// Remove agent
+sdk.remove_agent("agent_id");
+```
+
+## Supported File Types
+
+- **Images**: JPEG, PNG, GIF, WebP, BMP
+- **Videos**: MP4, AVI, MOV, WebM (uploaded to cloud storage)
+- **Text**: Plain text, Markdown, HTML, JSON
+
+## Error Handling
+
+The SDK provides detailed error types:
+
+```rust
+use gemini_sdk::SDKError;
+
+match sdk.send_message(request).await {
+    Ok(response) => println!("Success: {}", response.content),
+    Err(SDKError::AgentNotFound(id)) => println!("Agent {} not found", id),
+    Err(SDKError::Attachment(msg)) => println!("Attachment error: {}", msg),
+    Err(SDKError::Api { status, message }) => println!("API error {}: {}", status, message),
+    Err(e) => println!("Other error: {}", e),
+}
+```
+
+## Examples
+
+Run the examples to see the SDK in action:
+
+```bash
+cargo run --example basic_usage
+```
+
+## License
+
+MIT License