Add kaizen context resolver for scheduled agent fleet discovery.

Implement discover_kaizen_scheduled_repos and discover_kaizen_projects per
kaizen-agentic ADR-005 contract: State Hub roster, roster.yaml filter, schedule
validation, and prepare_command emission. Register kaizen/resolver/shell source
types with unit tests and runbook dry-run instructions.

.env.example

@@ -25,7 +25,8 @@ ISSUE_SINK_TYPE=rest
 # ── Activity definitions ───────────────────────────────────────────────────────
 # Colon-separated paths to additional activity-definitions/ directories.
 # The local activity-definitions/ directory is always scanned.
-ACTIVITY_DEFINITION_DIRS=
+# Coulomb-loop kaizen engagement definitions (colon-separated for more roots).
+ACTIVITY_DEFINITION_DIRS=/home/worsch/coulomb-loop
 
 # ── Observability ─────────────────────────────────────────────────────────────
 # Prometheus metrics bind address (Temporal SDK metrics).