P6: convert monster to BaseDomain + BaseNodeAdapter + concern split

Refactor of monster to use the platform infrastructure (BaseDomain, BaseNodeAdapter,
ChildRouter, commandRegistry, statusBadge). Extracts concerns into
focused modules per .claude/refactor/MODULE_SPLIT.md generic template.
Tests stay green; CONTRACT.md generated; legacy aliases preserved.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

CONTRACT.md

@@ -0,0 +1,49 @@
+# monster — Contract
+
+Hand-maintained for Phase 6; the `## Inputs` table is generated from
+`src/commands/index.js` (see Phase 9 generator). Keep ≤ 80 lines.
+
+## Inputs (msg.topic on Port 0)
+
+| Canonical | Aliases (deprecated) | Payload | Effect |
+|---|---|---|---|
+| `cmd.start` | `i_start` | truthy/falsy | Sets `source.i_start`. On the next tick a sampling run begins if flow bounds validate. |
+| `set.schedule` | `monsternametijden` | array of AQUON rows (`SAMPLE_NAME`, `DESCRIPTION`, `SAMPLED_DATE`, `START_DATE`, `END_DATE`) | Stores the schedule and recomputes `nextDate` + `daysPerYear` for the configured `aquonSampleName`. |
+| `set.rain` | `rain_data` | per-location rain forecast (Open-Meteo shape) | Aggregates hourly precipitation into `sumRain` / `avgRain`; feeds the rain-scaled flow prediction. |
+| `data.flow` | `input_q` | `{ value: number, unit: string }` | Converts to m³/h and pushes into `flow.manual.atequipment`. Blends with measured-child flow in `getEffectiveFlow()`. |
+| `set.mode` | `setMode` | string | Delegated to `source.setMode()` if defined. Reserved for future use. |
+| `set.model-prediction` | `model_prediction` | numeric | Delegated to `source.setModelPrediction()` if defined. Reserved for future use. |
+
+Aliases log a one-time deprecation warning the first time they fire.
+
+## Outputs (msg.topic on Port 0/1/2)
+
+- **Port 0 (process):** `msg.topic = config.general.name`. Payload built
+  by `outputUtils.formatMsg(..., 'process')` from `getOutput()`. Delta-
+  compressed — only changed fields are emitted. Carries `pulse`, `running`,
+  `bucketVol`, `sumPuls`, `predFlow`, `m3PerPuls`, `q`, `timeLeft`,
+  `targetVolumeM3`, `targetProgressPct`, `targetDeltaL`, `predictedRateM3h`,
+  `sumRain`, `avgRain`, `nextDate`, plus the flat measurements snapshot.
+- **Port 1 (InfluxDB telemetry):** same shape as Port 0, formatted with the
+  `'influxdb'` formatter.
+- **Port 2 (registration):** at startup the node sends one
+  `{ topic: 'child.register', payload: <node.id>, positionVsParent, distance }`
+  to its parent.
+
+## Events emitted by `source.measurements.emitter`
+
+The `MeasurementContainer` fires `<type>.measured.<position>` whenever a
+matching series receives a new value. monster writes:
+
+- `flow.manual.atequipment` — operator-supplied manual flow.
+- `flow.measured.<position>` — re-emitted when a child measurement fires
+  (one of `flow.measured.upstream`, `flow.measured.downstream`,
+  `flow.measured.atequipment`).
+
+## Children accepted
+
+`measurement` only. The router subscribes to a child's
+`flow.measured.<position>` events when the child's `config.asset.type` is
+`'flow'` (or missing). Other asset types are ignored. monster has no
+position-based filtering — all three positions are wired and the latest
+value wins for each.