workflow-fix: launcher-level PYTHONPATH for managed lanes

Overview / Motivation

Auto-filed by the /daily Step-C parked-candidate sweep (2026-07-08) from a candidate parked on task #853 (recursion-guarded workflow-fix session).

Goal

Give every managed compute lane a uniform repo-root sys.path so deferred scripts.* imports stop being lane-dependent crashes.

Workflow gap

• Bug observed: Managed-lane drivers (GCP / SLURM / pod bootstrap) do not export PYTHONPATH=$WORKLOAD_ROOT, so repo root is absent from sys.path for every workload driver and each driver hand-rolls parents[N] sys.path inserts — the trap behind the #853 pod-side scripts.* import crash.
• Why it is a workflow gap: the fix targets the workflow surface (src/explore_persona_space/backends/gcp.py, src/explore_persona_space/backends/slurm.py, scripts/bootstrap_pod.sh); the originating session was recursion-guarded and could not route it.
• Confidence (emitter): see parked note below.

Proposed change (candidate diff sketch — refine in planning)

# gcp.py / slurm.py workload-cmd composition + bootstrap_pod.sh:
+ export PYTHONPATH="$WORKLOAD_ROOT${PYTHONPATH:+:$PYTHONPATH}"

Scope / surfaces

• Primary target: src/explore_persona_space/backends/gcp.py, src/explore_persona_space/backends/slurm.py, scripts/bootstrap_pod.sh
• Grep the workflow surface for the pattern before editing and update every hit; list them in the plan.

Constraints / invariants

• Workflow-surface only — never experiment code, configs/, or tasks/.
• scripts/workflow_lint.py --check-asks passes; ruff on touched files passes; if workflow.yaml or CLAUDE.md change, they stay consistent with the rule file.
• The spawned session runs under EPM_WORKFLOW_FIX_SESSION=1 / a workflow_fix_target: Provenance line — it MUST NOT auto-route its own subagents' workflow-fix candidates (recursion guard).

Provenance

• workflow_fix_target: src/explore_persona_space/backends/gcp.py, src/explore_persona_space/backends/slurm.py, scripts/bootstrap_pod.sh
• origin: parked candidate on task #853 at 2026-07-02T09:40:58Z

Verbatim parked note:

parked: EPM_WORKFLOW_FIX_SESSION — running under the workflow-fix recursion guard (workflow_fix_target Provenance), so these THREE candidates surfaced by the critic ensemble are LOGGED, not auto-routed (see .claude/rules/workflow-fix-on-bug.md § Recursion guard; plan v3 §13 has full detail):

1. target_file: scripts/workflow_lint.py — mechanical check flagging unguarded deferred scripts.* imports under src/explore_persona_space/experiments/** (needs AST/enclosing-scope reasoning to avoid false positives). confidence: medium.
2. target_file: src/explore_persona_space/backends/gcp.py, src/explore_persona_space/backends/slurm.py, scripts/bootstrap_pod.sh — launcher-level PYTHONPATH=$WORKLOAD_ROOT export so repo root is on sys.path for every managed-lane driver (masks, not removes, the trap for hand launches). confidence: medium.
3. target_file: src/explore_persona_space/orchestrate/env.py — canonical shared ensure_repo_root_on_syspath() helper replacing per-driver hand-rolled parents[N] copies. confidence: medium (src/** is outside the standard workflow-fix surface; needs scoping).

related_task: #853 (raised by critic ensemble round 1, 2026-07-02).