narrow: Implement rendering of with narrow operators.

Adds server and web app support for processing the new `with`
search operator.

Fixes part of #21505.

Co-authored-by: roanster007 <rohan.gudimetla07@gmail.com>
Co-authored-by: Tim Abbott <tabbott@zulip.com>

web/src/hash_parser.ts

@@ -127,6 +127,7 @@ export const allowed_web_public_narrows = [
     "search",
     "near",
     "id",
+    "with",
 ];
 
 export function is_spectator_compatible(hash: string): boolean {