bus: tc49/layout/state/wanted/point/<addr> — the address carries no system level

[iot49]

What

Decision 6 of ADR-0059. A point or signal address is the string the drawing carries and the hardware answers to, and the topic carries it as trailing levels with no system in front:

topic	payload fields	values
tc49/layout/state/wanted/point/<addr>	addr, position	position closed or thrown
tc49/layout/state/wanted/signal/<addr>	addr, aspect	aspect stop, caution or clear
tc49/layout/state/device/point/<addr>	addr, position	position closed or thrown

Whatever is wired subscribes tc49/layout/state/wanted/# and acts on the addresses it recognises, as traction already does. An address nobody answers to does no harm. Two systems that number a point alike both act, and that is the deployer's addressing to fix, not a topic level.

Scope

• docs/SYSTEM.md: the three rows, and the paragraph "a point or signal address names its system as its first level" goes.
• src/tc49/lib/inventory.py: the rows.
• src/tc49/store/drawing.py: the check that refuses an address naming no system goes; an address is any non-empty string.
• src/tc49/layout/interface.py, src/tc49/dccex/translator.py: no split("/") on an address; the translator acts on every point and signal address it hears.
• CONTEXT.md: Address (both entries) and Device vocabulary.
• Fixtures under bench/layouts/ that carry dccex/… addresses, and the UI's generated types.

Acceptance

• scripts/check.sh green.
• A drawing with a bare point address derives.
• The translator throws a point whose address is 5.

[iot49]

Closed to clear the tracker. The goal now is one working flow: draw a layout in the editor, save it, back it up, drag a train on, and drive it with the manual throttle. Anything still needed will be refiled against that.

[iot49]

Reopened. This is the ADR-0059 programme — the MQTT binding and one process per app, which is what removes the bridge. Closing it was a mistake.