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)).

plugins/kanban/dashboard/plugin_api.py

@@ -628,7 +628,7 @@ def update_task(task_id: str, payload: UpdateTaskBody, board: Optional[str] = Qu
                     status_code=400,
                     detail="Cannot set status to 'running' directly; use the dispatcher/claim path",
                 )
-            elif s in ("todo", "triage"):
+            elif s in {"todo", "triage"}:
                 ok = _set_status_direct(conn, task_id, s)
             else:
                 raise HTTPException(status_code=400, detail=f"unknown status: {s}")
@@ -742,7 +742,7 @@ def _set_status_direct(
             (task_id, run_id, json.dumps({"status": new_status}), int(time.time())),
         )
     # If we re-opened something, children may have gone stale.
-    if new_status in ("done", "ready"):
+    if new_status in {"done", "ready"}:
         kanban_db.recompute_ready(conn)
     return True
 
@@ -868,7 +868,7 @@ def bulk_update(payload: BulkTaskBody, board: Optional[str] = Query(None)):
                             ok = kanban_db.unblock_task(conn, tid)
                         else:
                             ok = _set_status_direct(conn, tid, "ready")
-                    elif s in ("todo", "running", "triage"):
+                    elif s in {"todo", "running", "triage"}:
                         ok = _set_status_direct(conn, tid, s)
                     else:
                         entry.update(ok=False, error=f"unknown status {s!r}")