v0.4: Official Houdini package system integration

- hermes_houdini_bridge.json: package descriptor (generated by install.sh)
- scripts/python/hermes_bridge_panel.py: moved to package-standard location
- python_panels/hermes_bridge.pypanel: registered in Windows menu
- install.sh: one-command installer (generates JSON with correct path)
- git clone + install.sh = fully installed; git pull = update
- Panel opens via Windows -> Hermes Bridge (no Python Shell needed)

install.sh

@@ -0,0 +1,39 @@
+#!/usr/bin/env bash
+# ──────────────────────────────────────────────────────────
+# Hermes-Houdini Bridge — Installer
+# Generates the Houdini package descriptor with the correct
+# absolute path to this repo, so Houdini finds the panel.
+# ──────────────────────────────────────────────────────────
+set -euo pipefail
+
+REPO_DIR="$(cd "$(dirname "$0")/.." && pwd)"
+HOUDINI_PREFS="${HOUDINI_USER_PREF_DIR:-$HOME/houdini21.0}"
+PACKAGES_DIR="$HOUDINI_PREFS/packages"
+DESCRIPTOR="$PACKAGES_DIR/hermes_houdini_bridge.json"
+
+echo "=== Hermes-Houdini Bridge Installer ==="
+echo "Repo:     $REPO_DIR"
+echo "Houdini:  $HOUDINI_PREFS"
+echo ""
+
+mkdir -p "$PACKAGES_DIR"
+
+cat > "$DESCRIPTOR" << EOF
+{
+    "hpath": "$REPO_DIR",
+    "env": [
+        {"HHB_PACKAGE": "$REPO_DIR"}
+    ],
+    "load_package_once": true,
+    "enable": "houdini_version >= '21.0'"
+}
+EOF
+
+echo "✓  Package descriptor installed"
+echo "   $DESCRIPTOR"
+echo ""
+echo "Restart Houdini, then find the panel under:"
+echo "   Windows → Hermes Bridge"
+echo ""
+echo "To update: cd $REPO_DIR && git pull"
+echo "To uninstall: rm $DESCRIPTOR"