Fix mention pills by allowing custom URL schemes in Lexical LinkNode

The previous fix (validateUrl on linkPlugin) only affected the link dialog,
not the markdown-to-Lexical import path. Lexical's LinkNode.sanitizeUrl()
converts agent:// and project:// URLs to about:blank because they aren't
in its allowlist. Override the prototype method to preserve these schemes
so mention chips render correctly.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

pnpm-lock.yaml

@@ -22,7 +22,7 @@ importers:
         version: 5.9.3
       vitest:
         specifier: ^3.0.5
-        version: 3.2.4(@types/debug@4.1.12)(@types/node@25.2.3)(jiti@2.6.1)(jsdom@28.1.0(@noble/hashes@2.0.1))(lightningcss@1.30.2)(tsx@4.21.0)
+        version: 3.2.4(@types/debug@4.1.12)(@types/node@25.2.3)(jiti@2.6.1)(jsdom@28.1.0)(lightningcss@1.30.2)(tsx@4.21.0)
 
   cli:
     dependencies:
@@ -583,6 +583,9 @@ importers:
       '@dnd-kit/utilities':
         specifier: ^3.2.2
         version: 3.2.2(react@19.2.4)
+      '@lexical/link':
+        specifier: 0.35.0
+        version: 0.35.0
       '@mdxeditor/editor':
         specifier: ^3.52.4
         version: 3.52.4(@codemirror/language@6.12.1)(@lezer/highlight@1.2.3)(@types/react-dom@19.2.3(@types/react@19.2.14))(@types/react@19.2.14)(react-dom@19.2.4(react@19.2.4))(react@19.2.4)(yjs@13.6.29)
@@ -685,7 +688,7 @@ importers:
         version: 6.4.1(@types/node@25.2.3)(jiti@2.6.1)(lightningcss@1.30.2)(tsx@4.21.0)
       vitest:
         specifier: ^3.0.5
-        version: 3.2.4(@types/debug@4.1.12)(@types/node@25.2.3)(jiti@2.6.1)(jsdom@28.1.0(@noble/hashes@2.0.1))(lightningcss@1.30.2)(tsx@4.21.0)
+        version: 3.2.4(@types/debug@4.1.12)(@types/node@25.2.3)(jiti@2.6.1)(jsdom@28.1.0)(lightningcss@1.30.2)(tsx@4.21.0)
 
 packages:
 
@@ -12164,7 +12167,7 @@ snapshots:
       - tsx
       - yaml
 
-  vitest@3.2.4(@types/debug@4.1.12)(@types/node@25.2.3)(jiti@2.6.1)(jsdom@28.1.0(@noble/hashes@2.0.1))(lightningcss@1.30.2)(tsx@4.21.0):
+  vitest@3.2.4(@types/debug@4.1.12)(@types/node@25.2.3)(jiti@2.6.1)(jsdom@28.1.0)(lightningcss@1.30.2)(tsx@4.21.0):
     dependencies:
       '@types/chai': 5.2.3
       '@vitest/expect': 3.2.4

ui/package.json

@@ -13,14 +13,15 @@
     "@dnd-kit/core": "^6.3.1",
     "@dnd-kit/sortable": "^10.0.0",
     "@dnd-kit/utilities": "^3.2.2",
+    "@lexical/link": "0.35.0",
     "@mdxeditor/editor": "^3.52.4",
     "@paperclipai/adapter-claude-local": "workspace:*",
     "@paperclipai/adapter-codex-local": "workspace:*",
     "@paperclipai/adapter-cursor-local": "workspace:*",
     "@paperclipai/adapter-gemini-local": "workspace:*",
+    "@paperclipai/adapter-openclaw-gateway": "workspace:*",
     "@paperclipai/adapter-opencode-local": "workspace:*",
     "@paperclipai/adapter-pi-local": "workspace:*",
-    "@paperclipai/adapter-openclaw-gateway": "workspace:*",
     "@paperclipai/adapter-utils": "workspace:*",
     "@paperclipai/shared": "workspace:*",
     "@radix-ui/react-slot": "^1.2.4",

ui/src/components/MarkdownEditor.tsx

@@ -26,11 +26,22 @@ import {
   thematicBreakPlugin,
   type RealmPlugin,
 } from "@mdxeditor/editor";
+import { LinkNode } from "@lexical/link";
 import { buildAgentMentionHref, buildProjectMentionHref } from "@paperclipai/shared";
 import { AgentIcon } from "./AgentIconPicker";
 import { applyMentionChipDecoration, clearMentionChipDecoration, parseMentionChipHref } from "../lib/mention-chips";
 import { cn } from "../lib/utils";
 
+/* ---- Allow custom mention URL schemes in Lexical's LinkNode ---- */
+// Lexical only allows http(s)/mailto/sms/tel by default, converting
+// everything else to about:blank.  We need agent:// and project://
+// to survive the markdown→Lexical import so mention chips render.
+const _origSanitizeUrl = LinkNode.prototype.sanitizeUrl;
+LinkNode.prototype.sanitizeUrl = function sanitizeUrl(url: string): string {
+  if (/^(agent|project):\/\//.test(url)) return url;
+  return _origSanitizeUrl.call(this, url);
+};
+
 /* ---- Mention types ---- */
 
 export interface MentionOption {