fix(runtime): restrict running effects to launch results and index history

Only the native detached launch (bg_job_id) or a bridge's explicit detachment
marks an operation's own work as RUNNING. A listing that reports some other
download/model/job as running settled normally; treating it as running left
the claim pending forever and could block required artifacts.

EffectHistory now indexes outcomes per effect once, removing a cubic scan in
assessment over long run lineages.

Adds adversarial coverage: browser page operations stay fail-closed through
the real dispatcher with effects enabled (no claim, never dispatched),
scheduler task triggers stay unverified admission, and assessment scales.

src/agent_runtime/effect_adapters.py

@@ -191,9 +191,12 @@ def _execution(result: Any, facts: ProducerFacts) -> ExecutionOutcome:
         return ExecutionOutcome.INTERRUPTED
     if facts.timed_out:
         return ExecutionOutcome.TIMED_OUT
+    # Only launch-shaped results mean this operation's own work continues:
+    # the native detached launch, or a bridge's explicit detachment. A listing
+    # that merely reports some other thing as "running" is not.
     if isinstance(result.get("bg_job_id"), str) and facts.exit_code == 0:
         return ExecutionOutcome.RUNNING
-    if result.get("detached") is True or result.get("status") == "running" or result.get("running") is True:
+    if result.get("detached") is True:
         return ExecutionOutcome.RUNNING
     denied = bool(result.get("blocked") or result.get("approval_required")
                   or facts.failure_kind.endswith("_denied"))