chore: ruff auto-fix PLR6201 — tuple → set in membership tests (#23937)

Replace  with  for all literal-tuple
membership tests. Set lookup is O(1) vs O(n) for tuple — consistent
micro-optimization across the codebase.

608 instances fixed via `ruff --fix --unsafe-fixes`, 0 remaining.
133 files, +626/-626 (net zero).

rl_cli.py

@@ -392,7 +392,7 @@ def main(
                 if not user_input:
                     continue
                 
-                if user_input.lower() in ('quit', 'exit', 'q'):
+                if user_input.lower() in {'quit', 'exit', 'q'}:
                     print("\n👋 Goodbye!")
                     break