feat(cli)!: default the scan target and add a JSON error contract

List local scans, resolve the active or most recent workspace automatically, and make logs, status, and stop use one canonical scan identity.

Add stable machine-readable failures, richer status output, explicit help errors, and seven-day Temporal retention. Treat absent Temporal pending-activity failures as absent whether the decoder represents them as `null` or missing.

BREAKING CHANGE: `status --json` now returns a fixed `failureMessage`. Read `partialReasons`, `agenticSast`, and `workflow.log` for diagnostic detail.

apps/cli/src/scan/derive.ts

@@ -70,6 +70,11 @@ function agentState(name: string, state: PipelineState | null, running: Set<stri
   return resolved ? 'skipped' : 'pending';
 }
 
+/**
+ * Only `failed`'s presence is used here, never its `.error` text: that string is the
+ * worker's raw error for the failed class, not vetted for display, so it is reduced to
+ * a boolean before reaching safeFailureDetail's fixed sentence.
+ */
 function agentError(name: string, state: PipelineState | null, byAgent: Map<string, RunningAgent>): string | undefined {
   const failed = state?.failedPipelines.find((f) => f.vulnType === agentClass(name));
   return (