Fix: Remove Message Validation (#79)

* fix: remove validation

* fix: remove sha256

Author: aoikurokawa

content/docs/hello-world-ncn/ncn-on-chain.mdx

@@ -308,18 +308,6 @@ if !ncn_vault_ticket
 
 This ensures that only properly registered and active participants can contribute to consensus.
 
-#### Message Validation
-
-Operators must submit messages that match the required format:
-
-```rust
-if !message.starts_with(&message_acc.keyword()) {
-    return Err(ProgramError::InvalidAccountData);
-}
-```
-
-This simple validation ensures that operators are responding to the correct challenge.
-
 ## Extending the Example
 
 1. Custom Validation Logic: Implement more complex validation rules for messages

content/docs/hello-world-ncn/overview.mdx

@@ -50,7 +50,7 @@ The NCN program demonstrates the core workflow of a consensus network:
 
     - **Operators performing computation and responding to messages**
 
-        - In our example, operators calculate a SHA-256 hash of the message
+        - In our example, operators calculate a hash of the message
 
         <Callout>
             In real NCNs, operator might: