Fix agent install/uninstall sudo placement, add dependency install hints

curl ... | API_URL=... bash runs as the invoking user, not root, so
"sudo" has to go right after the pipe (elevating bash) rather than
before curl — the old commands in the app UI, README, and scripts'
own usage comments put it in a spot that still failed the root check.
Also have install.sh/report-tasks.sh suggest the right package-manager
command (apt/dnf/yum/apk/pacman/zypper) when curl or jq is missing
instead of just failing, and bring the README up to date with both.

agent/linux/install.sh

@@ -1,9 +1,10 @@
 #!/usr/bin/env bash
 # Installs the Schedule Task Manager agent as a systemd timer.
 #
-# Usage:
+# Usage (must run as root — if not already root, put sudo right after the
+# pipe so it applies to bash, not to curl):
 #   curl -fsSL https://schedule.example.lan/agent/linux/install.sh | \
-#     API_URL=https://schedule.example.lan API_TOKEN=stm_xxx bash
+#     sudo API_URL=https://schedule.example.lan API_TOKEN=stm_xxx bash
 #
 set -euo pipefail
 
@@ -17,16 +18,41 @@ INTERVAL_MINUTES="${INTERVAL_MINUTES:-15}"
 
 if [[ "$EUID" -ne 0 ]]; then
   echo "This installer must be run as root (it installs a systemd timer)." >&2
+  echo "If you're piping from curl, put sudo right after the pipe so it elevates bash, not curl:" >&2
+  echo "  curl -fsSL ... | sudo API_URL=... API_TOKEN=... bash" >&2
   exit 1
 fi
 
-for bin in curl jq systemctl; do
+suggest_package_install() {
+  local pkg="$1"
+  if command -v apt-get >/dev/null 2>&1; then
+    echo "  sudo apt-get update && sudo apt-get install -y $pkg"
+  elif command -v dnf >/dev/null 2>&1; then
+    echo "  sudo dnf install -y $pkg"
+  elif command -v yum >/dev/null 2>&1; then
+    echo "  sudo yum install -y $pkg"
+  elif command -v apk >/dev/null 2>&1; then
+    echo "  sudo apk add $pkg"
+  elif command -v pacman >/dev/null 2>&1; then
+    echo "  sudo pacman -S $pkg"
+  elif command -v zypper >/dev/null 2>&1; then
+    echo "  sudo zypper install -y $pkg"
+  fi
+}
+
+for bin in curl jq; do
   if ! command -v "$bin" >/dev/null 2>&1; then
-    echo "Required dependency '$bin' is not installed." >&2
+    echo "Required dependency '$bin' is not installed. Try:" >&2
+    suggest_package_install "$bin" >&2
     exit 1
   fi
 done
 
+if ! command -v systemctl >/dev/null 2>&1; then
+  echo "systemctl was not found — this installer requires a systemd-based Linux distribution." >&2
+  exit 1
+fi
+
 echo "Installing Schedule Task Manager agent from $API_URL ..."
 
 curl -fsSL "$API_URL/agent/linux/report-tasks.sh" -o "$INSTALL_DIR/schedule-task-manager-agent.sh"
@@ -69,4 +95,4 @@ echo "Installed. Running an initial report now..."
 "$INSTALL_DIR/schedule-task-manager-agent.sh"
 
 echo "Done. The agent reports every ${INTERVAL_MINUTES} minute(s) via the 'schedule-task-manager-agent.timer' systemd timer."
-echo "To remove it later: curl -fsSL $API_URL/agent/linux/uninstall.sh | bash"
+echo "To remove it later: curl -fsSL $API_URL/agent/linux/uninstall.sh | sudo bash"