feat: regex hide rules (full-match) + right-click Hide button

- Hide rules now use anchored regex (^rule$) so plain text like
  "Speaker" matches exactly "Speaker", not "Gaming Speaker".
  To match a substring, use e.g. ".*Speaker.*". Rules that already
  start with ^ or end with $ are used as-is.
- Add "Hide" to node right-click context menu — adds the node's
  display name as a hide rule immediately

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

frontend/src/components/GraphCanvas.svelte

@@ -114,9 +114,15 @@
   }
 
   function isNodeHidden(nd: { name: string; nick: string }): boolean {
-    const dn = displayName(nd).toLowerCase();
+    const dn = displayName(nd);
     for (const rule of $patchbay.hide_rules) {
-      if (dn === rule.toLowerCase()) return true;
+      try {
+        // Anchor to full match unless user already added anchors
+        const anchored = (rule.startsWith('^') || rule.endsWith('$')) ? rule : `^${rule}$`;
+        if (new RegExp(anchored, 'i').test(dn)) return true;
+      } catch {
+        if (dn.toLowerCase() === rule.toLowerCase()) return true;
+      }
     }
     return false;
   }
@@ -692,6 +698,11 @@
         renameInput = $patchbay.aliases?.[nodeContextMenu!.nodeName] ?? '';
         nodeContextMenu = null;
       }}>Rename</button>
+      <button onclick={() => {
+        const nd = $nodes.find(n => n.id === nodeContextMenu!.nodeId);
+        if (nd) addHideRule(displayName(nd));
+        nodeContextMenu = null;
+      }}>Hide</button>
       <button onclick={() => {
         fetch('/api/destroy-node', {
           method: 'POST',