nodes: what porting the house needed from the vocabulary

Four small things, each with a device behind it.

An MQTT filter now routes what it subscribed to. `+` and `#` reached the
broker and were then looked up in an exact-match dict, so every message a
wildcard subscription received was dropped in silence.

`json_key` lifts a value out of the object a device wraps it in — Victron
publishes `{"value": 47}` on every path, which was otherwise a Python node
per port.

The trigger node learned `passthrough` and `wait_port`, because how long to
wait can be a value rather than a constant: a rollershutter takes 26 seconds
up and 28 down. A wait of zero sends nothing afterwards and still cancels
what the last message scheduled, which is how a stop is commanded once
instead of forever.

The HTTP sender takes fixed `query` parameters, so an API key is a secret
reference rather than a message on the canvas, and `send_inputs` off for a
request whose inputs are only a trigger.

Also: `delay` accepts fractional seconds, and `TZ` reaches the container, so
a cron expression means local time. Left unset it is UTC, as before.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

docs/reference/node-types.md

@@ -40,8 +40,15 @@ A node with *outputs only* subscribes; a node with *inputs* publishes.
 | `qos` | `0` | 0, 1 or 2 |
 | `retain` | `false` | on published messages |
 | `keepalive` | `60` | seconds |
+| `json_key` | — | key to lift out of an object payload; one for every port, or `{"port": "key"}` |
 
-Nodes sharing a broker share one connection.
+A topic may be a filter: `+` matches one level, `#` the rest. Everything a
+filter matches lands on the same port, so use one port per topic where the
+difference matters.
+
+`json_key` is for a device that wraps its reading — Victron publishes
+`{"value": 47}` on every path. Without it, a payload object is unwrapped only
+when it happens to carry the port's own name as a key.
 
 ### HTTP
 
@@ -56,6 +63,8 @@ Outputs only makes it a **webhook**: the engine mounts a route at
 | `method` | `POST` | `GET` or `POST` |
 | `timeout` | `30` | seconds, sender mode |
 | `headers` | `{}` | |
+| `query` | `{}` | fixed query parameters; a value may be a secret reference |
+| `send_inputs` | `true` | off when the inputs only trigger the request |
 | `secret` | — | shared secret appended to the webhook URL; takes a secret reference |
 
 !!! warning "A webhook with no secret is open to anyone who can reach the host."
@@ -137,7 +146,7 @@ presses.
 
 | Setting | Default | Notes |
 |---|---|---|
-| `delay` | `0` | seconds to hold each message |
+| `delay` | `0` | seconds to hold each message, fractional |
 | `interval` | `0` | minimum seconds between forwards |
 | `mapping` | `{}` | input port → output port; paired in order when empty |
 | `cron` | — | five-field expression |
@@ -162,10 +171,18 @@ received.
 | `then` | `false` | sent when the wait expires; empty sends nothing |
 | `wait` | `60` | seconds of quiet before the second value |
 | `extend` | `true` | a value arriving during the wait starts it over |
+| `passthrough` | `false` | send the incoming value instead of `first` |
+| `wait_port` | — | an input carrying the wait, when it differs per message |
 
 The shape this exists for: *the door opened — turn the light on, and off again
 in two minutes unless it opens again.*
 
+`wait_port` covers the case where how long to wait is itself a value: a
+rollershutter takes 26 seconds up and 28 down, so the node that decides the
+direction says how long to run for as well. A wait of zero or less sends
+nothing afterwards — and still cancels whatever the last message scheduled,
+which is how a *stop* is commanded exactly once.
+
 ## Logic
 
 ### Switch