feat(rust/hermes-ipfs): ipfs persistent keypair

rust/hermes-ipfs/src/lib.rs

@@ -58,6 +58,18 @@ where N: NetworkBehaviour<ToSwarm = Infallible> + Send + Sync
         Self(IpfsBuilder::new())
     }
 
+    /// Create a new `IpfsBuilder` with an existing keypair.
+    ///
+    /// ## Parameters
+    /// - `keypair`: An existing keypair (can be `libp2p::identity::Keypair` or compatible
+    ///   type)
+    ///
+    /// ## Errors
+    /// Returns an error if the keypair is invalid.
+    pub fn with_keypair(keypair: impl connexa::builder::IntoKeypair) -> std::io::Result<Self> {
+        Ok(Self(IpfsBuilder::with_keypair(keypair)?))
+    }
+
     #[must_use]
     /// Set the default configuration for the IPFS node.
     pub fn with_default(self) -> Self {