Fix heavy-import-before-dotenv in issue1092 figure script (fleet-wide Step 9c thread-caps red)

Overview / Motivation

Auto-filed from an experiment-implementer report on task #1426 (round sampled-rollout-robustness, 2026-07-18): tests/test_shared_vm_thread_caps.py::test_no_new_torch_before_dotenv_vm_entrypoints FAILS fleet-wide on scripts/issue1092_prefixend_monitoring_combined_fig.py — the file imports matplotlib (line 19) and numpy (line 20) before any load_dotenv( call (0 load_dotenv( calls in the file). Every branch's Step 9c mapped-test gate that touches a thread-caps-mapped file now trips on this pre-existing red (the #1426 round confirmed it fails identically with its own diff stashed).

Goal

Fix the import order in scripts/issue1092_prefixend_monitoring_combined_fig.py so the thread-caps gate passes: add the project wrapper from explore_persona_space.orchestrate.env import load_dotenv + a load_dotenv() call BEFORE the heavy imports (the same shape as scripts/issue1426_analyzer_figures.py / issue1426_pooled_gradient.py, fixed in 62f983e36e), then confirm uv run pytest tests/test_shared_vm_thread_caps.py is green.

Workflow gap

• Bug observed: pre-existing test red on main blocks every session's Step 9c gate whose diff maps to test_shared_vm_thread_caps.py.
• Why filed as infra: experiment-code file (out of workflow-fix auto-spawn scope) but it breaks the shared mechanical gate; 2-line fix, no science impact (figure script for completed #1092).
• Confidence (emitter): high
• verified-at-filing: sed -n '1,25p' scripts/issue1092_prefixend_monitoring_combined_fig.py | grep -n 'import\|load_dotenv' → matplotlib line 19 / numpy line 20, 0 load_dotenv( calls in file (grep -c = 0); no open task mentions the file (repo-wide task-body grep, 2026-07-18)

Constraints

• Fix the SOURCE file only; run uv run pytest tests/test_shared_vm_thread_caps.py + ruff on the touched file.