feat: PersistentHugr implements HugrView (#2202)

Closes #2095

---------

Co-authored-by: Agustín Borgna <121866228+aborgna-q@users.noreply.github.com>

Author: lmondada

hugr-core/src/hugr/internal.rs

@@ -6,6 +6,7 @@ use std::sync::OnceLock;
 use itertools::Itertools;
 use portgraph::{LinkMut, LinkView, MultiPortGraph, PortMut, PortOffset, PortView};
 
+use crate::core::HugrNode;
 use crate::extension::ExtensionRegistry;
 use crate::{Direction, Hugr, Node};
 
@@ -91,6 +92,21 @@ impl PortgraphNodeMap<Node> for DefaultPGNodeMap {
     }
 }
 
+impl<N: HugrNode> PortgraphNodeMap<N> for std::collections::HashMap<N, Node> {
+    #[inline]
+    fn to_portgraph(&self, node: N) -> portgraph::NodeIndex {
+        self[&node].into_portgraph()
+    }
+
+    #[inline]
+    fn from_portgraph(&self, node: portgraph::NodeIndex) -> N {
+        let node = node.into();
+        self.iter()
+            .find_map(|(&k, &v)| (v == node).then_some(k))
+            .expect("Portgraph node not found in map")
+    }
+}
+
 impl HugrInternals for Hugr {
     type RegionPortgraph<'p>
         = &'p MultiPortGraph

hugr-core/src/hugr/patch/port_types.rs

@@ -4,7 +4,7 @@ use std::collections::HashMap;
 
 use crate::{IncomingPort, Node, OutgoingPort, Port};
 
-use derive_more::From;
+use derive_more::{From, derive::Into};
 
 /// A port in either the host or replacement graph.
 ///
@@ -19,7 +19,7 @@ pub enum BoundaryPort<HostNode, P> {
 }
 
 /// A port in the host graph.
-#[derive(Debug, Clone, Copy, From, PartialEq, Eq, PartialOrd, Ord, Hash)]
+#[derive(Debug, Clone, Copy, From, Into, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct HostPort<N, P>(pub N, pub P);
 
 /// A port in the replacement graph.

hugr-core/src/hugr/patch/simple_replace.rs

@@ -442,10 +442,8 @@ impl<HostNode: HugrNode> SimpleReplacement<HostNode> {
         Some(ReplacementPort(rep_output, incoming_port))
     }
 
-    /// Get the incoming ports in the input boundary of `subgraph` that
-    /// correspond to the given output port at the input node of `replacement`
-    ///
-    /// Return ports in `self.subgraph().incoming_ports()`.
+    /// Get the incoming port in `subgraph` that corresponds to the given
+    /// replacement input port.
     ///
     /// This panics if self.replacement is not a DFG.
     pub fn map_replacement_input(