Proper Matrix alerter support with client API

Matrix doesn't use a simple webhook URL — needs homeserver, room ID,
and bot token separately. Uses PUT /_matrix/client/v3/rooms/.../send
with Bearer token auth. Room ID is bash-encoded (! → %21, : → %3A)
to avoid Python dependency pre-setup. Also adds ntfy and plain
webhook as options under a typed alerter menu.

operator_setup.sh

@@ -374,12 +374,34 @@ fi
 
 # Network alerter webhook
 step "Network Alerter"
-prompt_default enable_alerter "Enable alerter webhook? (y/n)" "n"
+prompt_default enable_alerter "Enable online alert? (y/n)" "n"
+BB_ALERTER_TYPE=""
+BB_ALERTER_WEBHOOK=""
+BB_ALERTER_MATRIX_HS=""
+BB_ALERTER_MATRIX_ROOM=""
+BB_ALERTER_MATRIX_TOKEN=""
 if [[ "$enable_alerter" =~ ^[yY]$ ]]; then
-    prompt_default webhook_url "Webhook URL (Slack/Discord/Matrix)" ""
+    echo "  [1] Matrix"
+    echo "  [2] Slack / Discord (webhook URL)"
+    echo "  [3] ntfy"
+    prompt_default alerter_type "Alerter type (1-3)" "1"
+    if [[ "$alerter_type" == "1" ]]; then
+        BB_ALERTER_TYPE="matrix"
+        prompt_default matrix_hs "Homeserver URL" "https://m.example.org"
+        prompt_default matrix_room "Room ID (e.g. !abc123:homeserver)" ""
+        prompt_default matrix_token "Bot access token" ""
+        BB_ALERTER_MATRIX_HS="$matrix_hs"
+        BB_ALERTER_MATRIX_ROOM="$matrix_room"
+        BB_ALERTER_MATRIX_TOKEN="$matrix_token"
+    elif [[ "$alerter_type" == "2" ]]; then
+        BB_ALERTER_TYPE="webhook"
+        prompt_default webhook_url "Webhook URL" ""
         BB_ALERTER_WEBHOOK="$webhook_url"
-else
-    BB_ALERTER_WEBHOOK=""
+    elif [[ "$alerter_type" == "3" ]]; then
+        BB_ALERTER_TYPE="ntfy"
+        prompt_default ntfy_url "ntfy topic URL" ""
+        BB_ALERTER_WEBHOOK="$ntfy_url"
+    fi
 fi
 
 # ══════════════════════════════════════════════════════════════════════════════
@@ -405,7 +427,7 @@ if [[ "$BB_VPN" == "autossh" ]]; then
 else
     echo "VPN:                ${BOLD}${BB_VPN}${NC}"
 fi
-echo "Alerter:            ${BOLD}$([ -n "$BB_ALERTER_WEBHOOK" ] && echo "enabled" || echo "disabled")${NC}"
+echo "Alerter:            ${BOLD}$([ -n "$BB_ALERTER_TYPE" ] && echo "$BB_ALERTER_TYPE" || echo "disabled")${NC}"
 echo ""
 
 echo -n -e "${CYAN}Proceed with flashing and configuration? (y/n):${NC} "
@@ -550,9 +572,17 @@ BB_VPN="${BB_VPN}"
 BB_DEVICE_ID="${DEVICE_ID}"
 EOF
 
+if [[ -n "$BB_ALERTER_TYPE" ]]; then
+    echo "BB_ALERTER_TYPE=\"${BB_ALERTER_TYPE}\"" >> "${MOUNT_POINT}/root/bb-config.env"
+fi
 if [[ -n "$BB_ALERTER_WEBHOOK" ]]; then
     echo "BB_ALERTER_WEBHOOK=\"${BB_ALERTER_WEBHOOK}\"" >> "${MOUNT_POINT}/root/bb-config.env"
 fi
+if [[ -n "$BB_ALERTER_MATRIX_HS" ]]; then
+    echo "BB_ALERTER_MATRIX_HS=\"${BB_ALERTER_MATRIX_HS}\"" >> "${MOUNT_POINT}/root/bb-config.env"
+    echo "BB_ALERTER_MATRIX_ROOM=\"${BB_ALERTER_MATRIX_ROOM}\"" >> "${MOUNT_POINT}/root/bb-config.env"
+    echo "BB_ALERTER_MATRIX_TOKEN=\"${BB_ALERTER_MATRIX_TOKEN}\"" >> "${MOUNT_POINT}/root/bb-config.env"
+fi
 
 # Store Tailscale auth key if needed
 if [[ "$BB_VPN" == "tailscale" && -n "$TAILSCALE_KEY" ]]; then
@@ -664,13 +694,27 @@ SVCEOF
 fi
 
 # Network alerter
-if [[ -n "${BB_ALERTER_WEBHOOK:-}" ]]; then
+if [[ -n "${BB_ALERTER_TYPE:-}" ]]; then
     echo "[*] Sending online alert..."
-    BB_IP=$(curl -sf --max-time 5 https://api.ipify.org 2>/dev/null || hostname -I | awk '{print $1}')
-    BB_HOSTNAME=$(hostname)
-    curl -sf -X POST "$BB_ALERTER_WEBHOOK" \
+    _BB_IP=$(curl -sf --max-time 5 https://api.ipify.org 2>/dev/null || hostname -I | awk '{print $1}')
+    _BB_MSG="${BB_DEVICE_ID} online | ip: ${_BB_IP} | host: $(hostname)"
+
+    if [[ "${BB_ALERTER_TYPE}" == "matrix" ]]; then
+        _TXNID=$(date +%s%N)
+        _ROOM="${BB_ALERTER_MATRIX_ROOM//!/%21}"
+        _ROOM="${_ROOM//:/%3A}"
+        curl -sf -X PUT \
+            "${BB_ALERTER_MATRIX_HS}/_matrix/client/v3/rooms/${_ROOM}/send/m.room.message/${_TXNID}" \
+            -H "Authorization: Bearer ${BB_ALERTER_MATRIX_TOKEN}" \
+            -H "Content-Type: application/json" \
+            -d "{\"msgtype\":\"m.text\",\"body\":\"${_BB_MSG}\"}" || true
+    elif [[ "${BB_ALERTER_TYPE}" == "ntfy" ]]; then
+        curl -sf -X POST "${BB_ALERTER_WEBHOOK}" -d "${_BB_MSG}" || true
+    else
+        curl -sf -X POST "${BB_ALERTER_WEBHOOK}" \
             -H 'Content-Type: application/json' \
-        -d "{\"text\":\"BigBrother ${BB_DEVICE_ID} online | ip: ${BB_IP} | host: ${BB_HOSTNAME}\"}" || true
+            -d "{\"text\":\"${_BB_MSG}\"}" || true
+    fi
 fi
 
 echo "[+] First-boot complete: $(date)"