tester(ET): auto-commit from tester run_id=403

resolve_agent_effort returned '' for all agents in prod because empty
ORCH_AGENT_EFFORT_*= env vars clobber pydantic class-defaults, leaving no
non-empty floor to fall back to -> --effort never reached the Claude CLI.

Add a level-4 per-role floor in resolve_agent_effort (src/agents/launcher.py):
_agent_effort_floor reads the declared class-default of agent_effort_<agent>
(model_fields[...].default), which a present-but-empty env cannot override.
Floor applies only when levels 1-3 are empty and BEFORE validation, so a typo
(non-empty) still drops to '' (never-break ORCH-41) and explicit env/override
still wins (priority preserved). config.py: agent_effort_developer high->xhigh
(single source of truth; floor follows automatically).

Refs: ORCH-081

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

docs/work-items/ORCH-081/15-staging-log.md

@@ -0,0 +1,27 @@
+---
+staging_status: SUCCESS
+timestamp: 2026-06-08T19:47:45+00:00
+base_url: http://localhost:8501
+---
+
+# Staging Gate Log
+
+Staging test suite completed. Exit code 0 → advance.
+
+Canonical run inside the `orchestrator-staging` container (ORCH-048, ADR-001) via the
+Docker Engine API over the unix socket (docker CLI unavailable in the agent container):
+
+```
+python3 /repos/orchestrator/scripts/staging_check.py --base-url http://localhost:8501 --mode stub
+```
+
+Result: **8/10 checks PASS**, all REAL checks green.
+
+```
+INFRA-WAIVED: C9a Branch appears in orchestrator-sandbox, C9b Analyst job enqueued in staging queue (known sandbox-infra; real checks green)
+VERDICT: SUCCESS (exit 0) — SUCCESS (infra-waived): ['C9a Branch appears in orchestrator-sandbox', 'C9b Analyst job enqueued in staging queue'] are known sandbox-infra checks; all real checks green
+```
+
+The two waived checks (C9a/C9b) are the known sandbox-infra-only checks tolerated under
+ORCH-061 (SANDBOX bot accounts are not members of the sandbox Plane project — not a pipeline
+regression). All pipeline (REAL) checks A1–A3, B4–B6, C7–C8 passed.