use pql --with-context for ticket detail loading

Replaces the N+1 parent-chain walk (one IPC call per ancestor, one
per decision ref) with a single pql ticket show --with-context call.
pql now returns ancestors and decisions arrays inline.

Updates PqlClient.ticketShow to accept withContext/withChildren flags,
removes the obsolete withDecision flag.

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

lib/src/daemon/pql_commands.dart

@@ -200,8 +200,9 @@ void registerPqlCommands(DaemonDispatcher d, PqlClient pql) {
     try {
       final result = await pql.ticketShow(
         id,
-        withDecision: req.args['withDecision'] as bool? ?? false,
+        withContext: req.args['withContext'] as bool? ?? false,
         withBlockers: req.args['withBlockers'] as bool? ?? false,
+        withChildren: req.args['withChildren'] as bool? ?? false,
       );
       return IpcResponse.ok(id: req.id, data: result);
     } on PqlException catch (e) {