Add client/install.sh; fix server/install.sh paths after move

server/install.sh was broken after moving into server/: SCRIPT_DIR now
resolves to the server/ subdirectory, so requirements path, log dir, and
systemd WorkingDirectory all pointed at wrong locations. Introduce REPO_DIR
(parent of SCRIPT_DIR) and use it throughout.

client/install.sh creates a venv at client/.venv, installs
client/requirements.txt, and writes a client/run.sh launcher.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

client/install.sh

@@ -0,0 +1,67 @@
+#!/usr/bin/env bash
+# CLIENT installer — sets up the we_monitor GUI client.
+# Does NOT install the server (see server/install.sh).
+#
+# Fresh install:
+#   chmod +x install.sh
+#   ./install.sh
+#
+# Update (code already pulled via git):
+#   ./install.sh
+
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+REPO_DIR="$(dirname "$SCRIPT_DIR")"
+
+VENV="$SCRIPT_DIR/.venv"
+PYTHON="$VENV/bin/python"
+
+IS_UPDATE=false
+if [[ -x "$PYTHON" ]]; then
+    IS_UPDATE=true
+fi
+
+if $IS_UPDATE; then
+    echo "==> we_monitor GUI updater"
+else
+    echo "==> we_monitor GUI installer"
+fi
+echo "    Project : $REPO_DIR"
+echo "    User    : $USER"
+echo ""
+
+# ── 1. virtual environment ────────────────────────────────────────────────────
+if [[ ! -x "$PYTHON" ]]; then
+    echo "==> Creating virtual environment : $VENV"
+    python3 -m venv "$VENV"
+else
+    echo "==> Virtual environment exists   : $VENV"
+fi
+
+echo "==> Installing / updating dependencies"
+"$VENV/bin/pip" install --quiet --upgrade pip
+"$VENV/bin/pip" install --quiet --upgrade -r "$SCRIPT_DIR/requirements.txt"
+echo "    Python  : $PYTHON"
+echo ""
+
+# ── 2. launcher script ────────────────────────────────────────────────────────
+LAUNCHER="$SCRIPT_DIR/run.sh"
+cat > "$LAUNCHER" <<EOF
+#!/usr/bin/env bash
+exec "$PYTHON" "$SCRIPT_DIR/gui_client.py" "\$@"
+EOF
+chmod +x "$LAUNCHER"
+echo "==> Launcher written             : $LAUNCHER"
+
+echo ""
+echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
+if $IS_UPDATE; then
+    echo " Update complete."
+else
+    echo " Installation complete."
+    echo ""
+    echo " Start the GUI:"
+    echo "        $LAUNCHER"
+fi
+echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"