docs(contract): add worked msg examples for every input + output port

Reference-Contracts.md now carries a concrete `msg = { topic, payload, ... }`
example for each of the 7 input topics (plus the built-in query.units) and for
all three output ports (Port 0 process, Port 1 InfluxDB, Port 2 registration),
plus the emitter-event shape. Shapes verified against commandRegistry unit
normalisation and the process/influxdb formatters. Examples sit outside the
AUTOGEN markers so `npm run wiki:all` stays a no-op on them.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

wiki/Reference-Contracts.md

@@ -27,6 +27,48 @@ The **Unit** column reflects each descriptor's `units: { measure, default }` dec
 
 <!-- END AUTOGEN: topic-contract -->
 
+### Input message examples
+
+One worked `msg` per accepted topic. Send these into **Port 0**. For unit-bearing
+topics the commandRegistry converts `msg.unit` (or a `{ value, unit }` payload) to
+the default unit *before* the handler runs &mdash; so the unit is optional and any
+[compatible unit](https://gitea.wbd-rd.nl/RnD/EVOLV/wiki/Topic-Conventions) is accepted.
+
+```js
+// 1. set.mode  — switch control strategy
+msg = { topic: 'set.mode', payload: 'manual' };        // manual | levelbased | flowbased | none
+
+// 2. child.register — register a child (usually arrives on Port 2 from the child;
+//    this is the manual form). payload = the child node's Node-RED id.
+msg = { topic: 'child.register', payload: 'a1b2c3d4.ef567', positionVsParent: 'upstream' };
+//    positionVsParent: upstream | downstream | atequipment   (or in | out for predicted-flow children)
+
+// 3. cmd.calibrate.volume — seed the predicted-volume integrator (default m³)
+msg = { topic: 'cmd.calibrate.volume', payload: 12.5 };            // 12.5 m³
+msg = { topic: 'cmd.calibrate.volume', payload: 12500, unit: 'L' }; // 12 500 L → auto-converted to 12.5 m³
+
+// 4. cmd.calibrate.level — seed the predicted level (default m)
+msg = { topic: 'cmd.calibrate.level', payload: 1.8 };  // 1.8 m
+
+// 5. set.inflow — push a measured inflow (default m³/h)
+msg = { topic: 'set.inflow', payload: 45 };                                       // 45 m³/h
+msg = { topic: 'set.inflow', payload: 12.5, unit: 'L/s' };                        // 12.5 L/s → 45 m³/h
+msg = { topic: 'set.inflow', payload: { value: 45, unit: 'm3/h' }, timestamp: 1716998400000 };
+
+// 6. set.outflow — push a measured/forced outflow (default m³/h)
+msg = { topic: 'set.outflow', payload: 30 };           // 30 m³/h drawn from the basin
+
+// 7. set.demand — operator outflow setpoint (default m³/h); ignored unless mode === 'manual'
+msg = { topic: 'set.demand', payload: 120 };           // 120 m³/h
+
+// Built-in (every EVOLV node): query.units — ask which units each topic accepts.
+// Replies on Port 0 with { topic:'query.units', payload:{ node, units } }.
+msg = { topic: 'query.units', payload: null };
+```
+
+> Deprecated aliases behave identically and log a one-time warning, e.g.
+> `{ topic: 'q_in', payload: 45 }` ≡ `set.inflow`, `{ topic: 'Qd', payload: 120 }` ≡ `set.demand`.
+
 ---
 
 ## Data model &mdash; `getOutput()` shape
@@ -75,6 +117,52 @@ Sample values come from a stub instantiation in `wikiGen` &mdash; in a live depl
 > - `mode` &mdash; string, the active control strategy (`levelbased` / `manual` / `flowbased` / `none`). Echoes the most recent `set.mode` input.
 > - `manualDemand` &mdash; number (m³/h) or `null`. The operator outflow setpoint last accepted via `set.demand`; `null` outside `manual` mode.
 
+### Output message examples
+
+The node emits on three ports every tick (`outputUtils.formatMsg`). Port 0 / Port 1
+fire only when at least one field changed (delta-compression); Port 2 fires once at
+startup. `topic` is the station's configured name (here `"PS-Influent-01"`).
+
+```js
+// Port 0 — process data. payload = only the keys that changed this tick.
+msg = {
+  topic: 'PS-Influent-01',
+  payload: {
+    mode: 'levelbased',
+    direction: 'filling',
+    percControl: 25,
+    'level.predicted.atequipment.default': 3.25,   // m
+    'volume.predicted.atequipment.default': 32.5,  // m³
+    timeleft: 400,                                  // s, or null when steady
+    manualDemand: null                              // m³/h, or null outside manual mode
+  }
+};
+
+// Port 1 — InfluxDB telemetry. Same changed fields, wrapped for the InfluxDB node.
+msg = {
+  topic: 'PS-Influent-01',
+  payload: {
+    measurement: 'PS-Influent-01',
+    fields: { percControl: 25, 'volume.predicted.atequipment.default': 32.5 },
+    tags: { id: 'a1b2c3d4.ef567', softwareType: 'pumpingstation', type: 'pumpingStation' },
+    timestamp: '2026-05-29T10:00:00.000Z'           // Date
+  }
+};
+
+// Port 2 — registration handshake, sent once at startup to the upstream parent.
+msg = {
+  topic: 'child.register',
+  payload: 'a1b2c3d4.ef567',                         // this node's id
+  positionVsParent: 'atEquipment',
+  distance: null
+};
+```
+
+> **Child-facing events** are not Port messages &mdash; they fire on
+> `source.measurements.emitter` as `<type>.<variant>.<position>`, e.g. event
+> `volume.predicted.atequipment` with payload `{ value: 32.5, unit: 'm3', timestamp }`.
+> Parents subscribe by event name.
+
 ---
 
 ## Configuration schema &mdash; editor form to config keys