fix: suppress all compiler warnings

- mcp_server.rs: #[allow(dead_code)] on NotificationCallback type alias and get_notification_sender method
- handlers/mod.rs: #[allow(dead_code)] on past_complete_month helper
- Cargo.toml: move maintenance key into [package.metadata] (was invalid at package level)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Cargo.toml

@@ -11,6 +11,8 @@ keywords = ["mt5", "mql5", "trading", "mcp", "backtest"]
 categories = ["finance", "development-tools"]
 homepage = "https://github.com/masdevid/mt5-quant"
 documentation = "https://github.com/masdevid/mt5-quant"
+
+[package.metadata]
 maintenance = { status = "actively-developed" }
 
 [[bin]]

src/mcp_server.rs

@@ -4,6 +4,7 @@ use tokio::sync::{mpsc, Mutex};
 
 use crate::{models::Config as ModelsConfig, tools::ToolHandler, McpError, McpRequest, McpResponse};
 
+#[allow(dead_code)]
 type NotificationCallback = Arc<dyn Fn(&str, serde_json::Value) + Send + Sync>;
 
 /// Auto-verify result stored after first initialization
@@ -59,6 +60,7 @@ impl McpServer {
         *handler_guard = Some(new_handler);
     }
 
+    #[allow(dead_code)]
     pub async fn get_notification_sender(&self) -> Option<mpsc::UnboundedSender<Notification>> {
         let guard = self.notification_tx.lock().await;
         guard.clone()

src/tools/handlers/mod.rs

@@ -179,6 +179,7 @@ pub(crate) fn dir_size(path: &Path) -> u64 {
         .sum()
 }
 
+#[allow(dead_code)]
 pub(crate) fn past_complete_month() -> (String, String) {
     let now = chrono::Utc::now();
     let today = chrono::NaiveDate::from_ymd_opt(now.year(), now.month(), 1)