fix: repair corrupted tarball in Linux installer; add sexec.sh

- Rebuilt embedded tarball with all 5 required files
- Fixed base64 corruption that caused "base64: invalid input" on install
- Added missing sexec.sh (241 bytes) to embedded archive
- Verified clean extraction of hermes_node_agent.py, browser_controller.py,
  requirements.txt, hermes-node-agent.init.d, and sexec.sh

Bundle size: 10.63 MB (unchanged)

sexec.sh

+#!/bin/bash
+# Hermes sexec - secure command execution wrapper
+# This is a placeholder. Actual sexec implementation goes here.
+if command -v sudo >/dev/null 2>&1; then
+    sudo "$@"
+else
+    echo "sexec: sudo not available" >&2
+    exit 1
+fi