chore: aligned blocked-todo test, added robomp sandbox scaffolding

- Aligned the blocked-todo reconciliation test with the debounced
  subagent-lifecycle observer on main (fake timers + 100ms advance).
- Carries in-progress robomp queue/sandbox/config scaffolding from the
  shared worktree (.env.example, config.py, queue.py, sandbox.py).

python/robomp/.env.example

@@ -114,6 +114,11 @@ ROBOMP_MAX_CONCURRENCY=8
 ROBOMP_TASK_TIMEOUT_SECONDS=2400
 ROBOMP_TASK_TIMEOUT_HARD_GRACE_SECONDS=60
 ROBOMP_REQUEST_TIMEOUT_SECONDS=120
+# Strip node_modules + the per-workspace bun cache after every task run (and
+# once at boot). Deps are reinstalled at each run start, so this only costs a
+# re-download per run — leaving it on keeps disk usage bounded by concurrency
+# instead of by the number of open issues.
+ROBOMP_RECLAIM_WORKSPACE_CACHES=true
 
 
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