feat(agent): agent_prepare_context tool + context_scout subagent (#3949)

scripts/debug/cli.sh

@@ -24,6 +24,9 @@ Commands:
         Inspect saved debug-log files. `last` shows the most recent.
   harness-cache-audit [options]
         Run live harness turns over JSON-RPC and summarize transcript token/cache deltas.
+  agent-prepare-context-audit [options]
+        Live-audit the agent_prepare_context tool: force it per query, print the
+        returned context bundle, scout thoughts, and tokens/cache/cost.
   goals-live [options]
         Live-test the memory_goals flow (list/add/edit/delete + reflect enrichment),
         printing the goals_agent's thoughts, tool calls, token usage and cost.
@@ -49,6 +52,9 @@ case "$cmd" in
   harness-cache-audit)
     exec node "$here/harness-cache-audit.mjs" "$@"
     ;;
+  agent-prepare-context-audit)
+    exec node "$here/agent-prepare-context-audit.mjs" "$@"
+    ;;
   goals-live)
     exec node "$here/goals-live.mjs" "$@"
     ;;