Add delete_decision tool for removing redundant ADRs

server/src/handlers/meta.rs

@@ -76,6 +76,37 @@ impl McpTool for QueryDecisionsHandler {
     }
 }
 
+pub struct DeleteDecisionHandler;
+
+#[async_trait]
+impl McpTool for DeleteDecisionHandler {
+    fn name(&self) -> &'static str {
+        "delete_decision"
+    }
+
+    fn schema(&self) -> Value {
+        crate::mcp::tool_def::<crate::tools::DeleteDecisionTool>("delete_decision", "Delete an architectural decision record")
+    }
+
+    async fn execute(&self, args: Value, state: Arc<MemoryState>) -> Result<String, String> {
+        let req: crate::tools::DeleteDecisionTool = serde_json::from_value(args).map_err(|e| e.to_string())?;
+        let mut found = false;
+        state.adrs.modify(|adrs| {
+            if let Some(pos) = adrs.iter().position(|a| a.id == req.id) {
+                adrs.remove(pos);
+                found = true;
+            }
+        });
+        
+        if found {
+            state.rebuild_index().await;
+            Ok("Decision deleted successfully".to_string())
+        } else {
+            Err("Decision not found".to_string())
+        }
+    }
+}
+
 pub struct LogErrorFixHandler;
 
 #[async_trait]