fix: installer self-elevates with script PTY instead of external sudo chain

- agent-install.sh and agent-uninstall.sh now detect if running as root
  at startup and re-execute via 'script -qc sudo bash' if needed
- AgentService commands simplified: just write to /tmp and run bash,
  the scripts handle privilege escalation internally
- Fixes exit code propagation: the script's exit code now correctly
  flows back through exec -> script -> sudo -> bash -> SSH

install/agent-install.sh

@@ -1,7 +1,6 @@
 #!/bin/bash
 # ServerManager Agent Installer
 # Usage: bash agent-install.sh <SERVER_URL> <AGENT_KEY> [INTERVAL]
-set -e
 
 SERVER_URL="${1:-}"
 AGENT_KEY="${2:-}"
@@ -12,6 +11,14 @@ if [ -z "$SERVER_URL" ] || [ -z "$AGENT_KEY" ]; then
     exit 1
 fi
 
+# Self-elevate if not running as root
+if [ "$(id -u)" -ne 0 ]; then
+    if command -v script >/dev/null 2>&1; then
+        exec script -q -c "sudo bash '$0' '$1' '$2' '$3'" /dev/null
+    fi
+    exec sudo bash "$0" "$@"
+fi
+
 AGENT_BIN="/usr/local/bin/servermanager-agent"
 CONFIG_DIR="/etc/servermanager"
 CONFIG_FILE="$CONFIG_DIR/agent.conf"

install/agent-uninstall.sh

@@ -1,6 +1,13 @@
 #!/bin/bash
 # ServerManager Agent Uninstaller
-set -e
+
+# Self-elevate if not running as root
+if [ "$(id -u)" -ne 0 ]; then
+    if command -v script >/dev/null 2>&1; then
+        exec script -q -c "sudo bash '$0'" /dev/null
+    fi
+    exec sudo bash "$0"
+fi
 
 AGENT_BIN="/usr/local/bin/servermanager-agent"
 CONFIG_DIR="/etc/servermanager"