refactor(hpc): migrate to PBS/vsc-venv, reorganise scripts under scripts/hpc/

- Replace Slurm headers with PBS (#PBS) directives
- Replace manual module+venv logic with vsc-venv --activate
- Cluster selection via 'module swap cluster/<name>' before qsub
- MUJOCO_GL=egl retained: required for headless physics sim and video rendering
- Delete deprecated scripts/hpc_install.sh and scripts/hpc_train.slurm

scripts/hpc/install.sh

@@ -0,0 +1,33 @@
+#!/bin/bash
+# scripts/hpc/install.sh — Run once on a login node (donphan) to set up the
+# project's Python virtual environment using the official vsc-venv wrapper.
+#
+# Usage (from project root):
+#   bash scripts/hpc/install.sh
+#
+# Prerequisites:
+#   - Connected to VSC via the web portal (HPC Login → Shell tmux)
+#   - Project cloned to $VSC_DATA or $VSC_HOME
+#   - Run from the project root directory
+
+set -euo pipefail
+
+echo "==> Loading vsc-venv module..."
+module load vsc-venv
+
+echo "==> Activating virtual environment (created per-cluster in \$VSC_DATA)..."
+# vsc-venv transparently creates and manages a per-cluster venv in $VSC_DATA,
+# loading the modules listed in env/hpc/modules.txt and pip-installing anything
+# in env/hpc/requirements.txt that is not already satisfied.
+source vsc-venv --activate \
+    --modules env/hpc/modules.txt \
+    --requirements env/hpc/requirements.txt
+
+echo "==> Registering Jupyter kernel..."
+python -m ipykernel install --user --name="sel3_${VSC_INSTITUTE_CLUSTER}" \
+    --display-name "SEL3 (${VSC_INSTITUTE_CLUSTER})"
+
+echo ""
+echo "✅ Environment ready. Kernel: sel3_${VSC_INSTITUTE_CLUSTER}"
+echo "   Activate in future sessions with:"
+echo "     module load vsc-venv && source vsc-venv --activate --modules env/hpc/modules.txt"