refactor(client): remove Engine::builder() method and update imports

- Remove the deprecated Engine::builder() method from the Engine struct
- Update all examples to use EngineBuilder::new() instead of Engine::builder()
- Update import statements to remove Engine from client module exports
- Update documentation examples to reflect the new EngineBuilder usage
- Update README.md to remove Engine from the import statement

Author: zTgx

README.md

@@ -60,7 +60,7 @@ vectorless = "0.1"
 ```
 
 ```rust
-use vectorless::client::{Engine, EngineBuilder, IndexContext};
+use vectorless::client::{EngineBuilder, IndexContext};
 
 #[tokio::main]
 async fn main() -> vectorless::Result<()> {

examples/rust/advanced.rs

@@ -16,15 +16,15 @@
 //! cargo run --example advanced
 //! ```
 
-use vectorless::{Engine, IndexContext};
+use vectorless::{EngineBuilder, IndexContext};
 
 #[tokio::main]
 async fn main() -> vectorless::Result<()> {
     println!("=== Vectorless Advanced Example (Full Configuration) ===\n");
 
     // Method 1: Use explicit config file path
     // This loads all settings from the specified config file
-    let client = Engine::builder()
+    let client = EngineBuilder::new()
         .with_config_path("./config.toml") // or "./my_vectorless.toml"
         .build()
         .await

examples/rust/basic.rs

@@ -11,14 +11,14 @@
 //! cargo run --example basic
 //! ```
 
-use vectorless::{Engine, IndexContext};
+use vectorless::{EngineBuilder, IndexContext};
 
 #[tokio::main]
 async fn main() -> vectorless::Result<()> {
     println!("=== Vectorless Basic Example ===\n");
 
     // 1. Create a client
-    let client = Engine::builder()
+    let client = EngineBuilder::new()
         .with_workspace("./workspace")
         .build()
         .await

examples/rust/batch_processing.rs

@@ -775,7 +775,7 @@ vectorless --version
 4. Query!
 
 ```rust
-let client = Engine::builder().build()?;
+let client = EngineBuilder::new().build()?;
 let doc_id = client.index("./doc.md").await?;
 let result = client.query(&doc_id, "What is this?").await?;
 ```

examples/rust/custom_config.rs

@@ -12,7 +12,7 @@
 //! cargo run --example custom_config
 //! ```
 
-use vectorless::{Engine, IndexContext};
+use vectorless::{EngineBuilder, IndexContext};
 
 #[tokio::main]
 async fn main() -> vectorless::Result<()> {
@@ -32,7 +32,7 @@ async fn main() -> vectorless::Result<()> {
     // ============================================================
 
     // Example: Use DeepSeek API
-    let client = Engine::builder()
+    let client = EngineBuilder::new()
         .with_workspace("./workspace")
         .with_model("deepseek-chat", Some("sk-your-deepseek-key".to_string()))
         .with_endpoint("https://api.deepseek.com/v1")
@@ -64,23 +64,23 @@ async fn main() -> vectorless::Result<()> {
     // ============================================================
 
     // Azure OpenAI:
-    // let client = Engine::builder()
+    // let client = EngineBuilder::new()
     //     .with_workspace("./workspace")
     //     .with_model("gpt-4o", Some("your-azure-key".to_string()))
     //     .with_endpoint("https://your-resource.openai.azure.com/openai/deployments/your-deployment")
     //     .build()
     //     .await?;
 
     // Local LLM (e.g., Ollama with OpenAI-compatible API):
-    // let client = Engine::builder()
+    // let client = EngineBuilder::new()
     //     .with_workspace("./workspace")
     //     .with_model("llama3", None)  // No API key needed
     //     .with_endpoint("http://localhost:11434/v1")
     //     .build()
     //     .await?;
 
     // Anthropic Claude (via OpenAI-compatible proxy):
-    // let client = Engine::builder()
+    // let client = EngineBuilder::new()
     //     .with_workspace("./workspace")
     //     .with_model("claude-3-5-sonnet-20241022", Some("sk-ant-...".to_string()))
     //     .with_endpoint("https://api.anthropic.com/v1")

examples/rust/custom_pilot.rs

@@ -242,7 +242,7 @@ fn main() {
     println!("use vectorless::Engine;");
     println!();
     println!("let pilot = Arc::new(KeywordPilot::new());");
-    println!("let engine = Engine::builder()");
+    println!("let engine = EngineBuilder::new()");
     println!("    .with_workspace(\"./workspace\")");
     println!("    .with_pilot(pilot)");
     println!("    .build()");

examples/rust/markdownflow.rs

@@ -19,7 +19,7 @@
 //! OPENAI_API_KEY=sk-... cargo run --example markdown_flow
 //! ```
 
-use vectorless::Engine;
+use vectorless::EngineBuilder;
 use vectorless::client::{IndexContext, IndexOptions};
 
 /// Sample markdown content for demonstration.
@@ -43,7 +43,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
     // Step 1: Create a Vectorless client (no API key needed - LLM config is automatic)
     println!("Step 1: Creating Vectorless client...");
 
-    let client = Engine::builder()
+    let client = EngineBuilder::new()
         .with_workspace("./workspace")
         .build()
         .await

rust/src/client/engine.rs

@@ -19,7 +19,7 @@
 //! # Example
 //!
 //! ```rust,no_run
-//! use vectorless::client::{Engine, EngineBuilder, IndexContext};
+//! use vectorless::client::{EngineBuilder, IndexContext};
 //!
 //! # #[tokio::main]
 //! # async fn main() -> Result<(), Box<dyn std::error::Error>> {
@@ -98,29 +98,6 @@ pub struct Engine {
 }
 
 impl Engine {
-    /// Create a builder for custom configuration.
-    #[must_use]
-    pub fn builder() -> super::EngineBuilder {
-        super::EngineBuilder::new()
-    }
-
-    /// Create a new client with default configuration.
-    ///
-    /// Note: Prefer using [`Engine::builder()`] for more control.
-    async fn new() -> Result<Self> {
-        let config = Config::default();
-        let workspace = Workspace::new("./workspace")
-            .await
-            .map_err(|e| Error::Workspace(e.to_string()))?;
-        Self::with_components(
-            config,
-            workspace,
-            PipelineRetriever::new(),
-            PipelineExecutor::new(),
-        )
-        .await
-    }
-
     // ============================================================
     // Constructor (for Builder)
     // ============================================================
@@ -184,7 +161,7 @@ impl Engine {
     /// # Example
     ///
     /// ```rust,no_run
-    /// use vectorless::client::{Engine, EngineBuilder, IndexContext, IndexMode};
+    /// use vectorless::client::{EngineBuilder, IndexContext, IndexMode};
     /// use vectorless::parser::DocumentFormat;
     ///
     /// # #[tokio::main]
@@ -596,11 +573,11 @@ impl std::fmt::Debug for Engine {
 
 #[cfg(test)]
 mod tests {
-    use super::*;
+    use super::super::EngineBuilder;
 
     #[test]
     fn test_engine_builder() {
-        let builder = Engine::builder();
+        let builder = EngineBuilder::new();
         // Builder exists
         let _ = builder;
     }

rust/src/client/index_context.rs

@@ -149,7 +149,7 @@ impl IndexSource {
 /// # Examples
 ///
 /// ```rust,no_run
-/// use vectorless::client::{Engine, EngineBuilder, IndexContext, IndexMode};
+/// use vectorless::client::{EngineBuilder, IndexContext, IndexMode};
 /// use vectorless::parser::DocumentFormat;
 ///
 /// # #[tokio::main]