bugfix(11): operate_rate must not sum a None

sum(t.steps > 0 and t.meta.get("clean") for t in rows) yields the right operand
of `and` when steps>0, so a trajectory whose meta lacks the "clean" key
contributes None and sum() raises TypeError. Wrap the predicate in bool() so it
counts trajectories that operated and are clean. Surfaced by mypy once posix-sdc
began shipping py.typed (Trajectory is now typed).

src/tiararodney/sekft/eval.py

@@ -80,7 +80,7 @@ def evaluate(base: str, adapter: str, scenarios_dir: Path, n: int,
     d = len(rows) or 1
     return {
         "n": len(rows),
-        "operate_rate": round(sum(t.steps > 0 and t.meta.get("clean") for t in rows) / d, 3),
+        "operate_rate": round(sum(bool(t.steps > 0 and t.meta.get("clean")) for t in rows) / d, 3),
         "terminate_rate": round(sum(t.terminal in ("exit", "panic") for t in rows) / d, 3),
         "verified_rate": round(sum(t.verified for t in rows) / d, 3),
         "clean_rate": round(sum(t.keep for t in rows) / d, 3),

src/tiararodney/sekft/resident.py

@@ -154,7 +154,7 @@ class Resident:
         d = len(rows) or 1
         m = {
             "n": len(rows),
-            "operate_rate": round(sum(t.steps > 0 and t.meta.get("clean") for t in rows) / d, 3),
+            "operate_rate": round(sum(bool(t.steps > 0 and t.meta.get("clean")) for t in rows) / d, 3),
             "terminate_rate": round(sum(t.terminal in ("exit", "panic") for t in rows) / d, 3),
             "verified_rate": round(sum(t.verified for t in rows) / d, 3),
             "clean_rate": round(sum(t.keep for t in rows) / d, 3),