internal_link: Escape single quotes in narrow links.

Add single quote (') to the list of characters to be replaced with their dot-encoded equivalents. This fixes an issue where URLs containing single quotes were not correctly parsed across different platforms and messaging clients.

Fixes #2105 with the behavior needed for consistent URL detection.

Author: moksha-hub

lib/model/internal_link.dart

@@ -14,9 +14,10 @@ const _hashReplacements = {
   "(": ".28",
   ")": ".29",
   ".": ".2E",
+  "'": ".27", // Escape single quotes to prevent URL detection issues
 };
 
-final _encodeHashComponentRegex = RegExp(r'[%().]');
+final _encodeHashComponentRegex = RegExp("[%()'.]");
 
 // Corresponds to encodeHashComponent in Zulip web;
 // see web/shared/src/internal_url.ts.