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)).

tests/cli/test_cli_init.py

@@ -99,7 +99,7 @@ class TestVerboseAndToolProgress:
     def test_tool_progress_mode_is_string(self):
         cli = _make_cli()
         assert isinstance(cli.tool_progress_mode, str)
-        assert cli.tool_progress_mode in ("off", "new", "all", "verbose")
+        assert cli.tool_progress_mode in {"off", "new", "all", "verbose"}
 
 
 class TestBusyInputMode: