nx_print_runtime_monitor.nx

nx_print_runtime_monitor.nx -- LIDAR-class spaghetti prevention from Klipper telemetry alone (no camera, no laser). Operator directive (2026-05-20 immediate): lidar spaghetti prevention. Bambu X1C has hardware LIDAR + camera for mid-print spaghetti detection. Substrate alternative for Qidi X-Max 3 (which has Klipper telemetry but no LIDAR): ingest the Moonraker WebSocket telemetry stream + flag anomalies indicative of spaghetti BEFORE they cascade into a 20-hour wasted print. Three detection paths -- all from REAL TELEMETRY, no guesswork: 1. STUCK_LAYER Z hasn't advanced for > N × expected_layer_time. Either the print stalled (firmware issue) or the head is moving without depositing material (spaghetti). 2. FLOW_ANOMALY Extruder accumulated material but Z + XY barely changed. Material is going somewhere -- if not into the print, into the air = spaghetti. 3. EXTRUDER_RUNAWAY Total extruded volume diverges from expected (computed from XY × layer_height × line_width). Suggests the extruder is grinding / over-pushing. All three compose existing substrate state + arithmetic. No heuristic thresholds beyond operator-supplied physical limits. Caller responsibility: pump telemetry events from nx_moonraker_io into nx_runtime_monitor_step + react to any issue verdict (pause print, alert operator, etc.). license_tier: ORIGINAL