Add a global search, and stop the sidebar logo squeezing

`GET /api/v1/search/` hands the client one flat index of everything worth
jumping to — flows and the nodes inside them, dashboards and the widgets on
them, panels, secrets, modules, workers and alert channels — and cmdk matches
it in the browser, so results narrow while typing without a round trip per
keystroke. A node hit is the one thing no list endpoint could answer: it opens
its flow with that node in focus.

The panel is reached from **Search** above Documentation in the sidebar, or
⌘K anywhere. The flow canvas palette moves to ⌘P, being the narrower of the two.

The panels dialog gains an address (`/dashboards?panels`) so a panel hit has
somewhere to land, and the sidebar logo gets `shrink-0`: the rail's width
animates while the logo is already back, and a flex item short of room is
squeezed rather than clipped.

docs/getting-started/facility-automation.md

@@ -134,7 +134,7 @@ safe, fan-in is free, and two flows can share a value by naming it.
 
 ### Read a sensor
 
-Press **Add node** (or ⌘K / Ctrl-K, which opens the command palette) and pick
+Press **Add node** (or ⌘P / Ctrl-P, which opens the command palette) and pick
 **MQTT**. In its panel on the right:
 
 - **Broker host** — your broker's hostname, `mosquitto` if you are using the