fix: make help command reachable by removing it from META_COMMANDS

help was in META_COMMANDS, so it dispatched to handleMetaCommand() which
threw "Unknown meta command: help". Removing it from the set lets the
dedicated else-if handler in handleCommand() execute correctly.

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

browse/src/server.ts

@@ -124,7 +124,7 @@ export const META_COMMANDS = new Set([
   'tabs', 'tab', 'newtab', 'closetab',
   'status', 'stop', 'restart',
   'screenshot', 'pdf', 'responsive',
-  'chain', 'diff', 'help',
+  'chain', 'diff',
   'url', 'snapshot',
 ]);