chore: ruff auto-fix PLR6201 resweep — tuple → set in membership tests (#27355)

Six days after #23937 (608 fixes) the codebase had accumulated 241 new
PLR6201 violations. Same mechanical `x in (...)` → `x in {...}` fix,
same zero-risk profile: set lookup is O(1) vs O(n) for tuple and the
two are semantically equivalent for hashable scalar membership tests.

All 241 instances fixed via `ruff check --select PLR6201 --fix
--unsafe-fixes`, zero remaining. Every changed value is a hashable
scalar (str/int/None/enum/signal); no risk of unhashable runtime
errors. No behavior change.

Test plan:
- 119 files changed, +244/-244 (net zero) — exactly one-line edits
- `ruff check` clean afterward
- Compile checks pass on the largest touched files (cli.py, run_agent.py,
  gateway/run.py, gateway/platforms/discord.py, model_tools.py)
- Subset broad test run on tests/gateway/ tests/hermes_cli/ tests/agent/
  tests/tools/: 18187 passed, 59 pre-existing failures (verified against
  origin/main with the same shape — identical failure count, identical
  category — all xdist test-order flakes unrelated to this change)

Follows the same template as PR #23937 ([tracker: #23972](https://github.com/NousResearch/hermes-agent/issues/23972)).

hermes_cli/auth.py

@@ -2610,7 +2610,7 @@ def _print_loopback_ssh_hint(redirect_uri: str, *, docs_url: str | None = None)
         return
     host = parsed.hostname or ""
     port = parsed.port
-    if host not in ("127.0.0.1", "::1", "localhost") or not port:
+    if host not in {"127.0.0.1", "::1", "localhost"} or not port:
         return
     print()
     print("Remote session detected. Your browser will redirect to")
@@ -5246,7 +5246,7 @@ def _login_xai_oauth(
                     reuse = input("Use existing credentials? [Y/n]: ").strip().lower()
                 except (EOFError, KeyboardInterrupt):
                     reuse = "y"
-                if reuse in ("", "y", "yes"):
+                if reuse in {"", "y", "yes"}:
                     config_path = _update_config_for_provider(
                         "xai-oauth",
                         existing.get("base_url", DEFAULT_XAI_OAUTH_BASE_URL),