Shell UI components

The shell provides the UI; a plugin declares what it wants. This is only an index — each component is documented in its own section, which stays the single source of truth.

`ctx.ui.*`	Declarative form in `ui.json`	What it is	Section
`Toolbar`	`toolbars` + `placements`	Command bar (global, per tab, per panel)	Menus, toolbars and command placements
`ContextMenu`	`menus` (`contextMenu`)	Right-click menu bound to a context	Menus, toolbars and command placements
`Tree`	`panel.tree`	Reactive tree fed by a slice path	Trees, lists and declarative panels
`List`	`panel.list`	Backward-compatible one-level tree alias	Trees, lists and declarative panels
`Table`	`panel.table` / view tables	Typed columns using registered value types	Tables
`Graph`	`panel.graph` / view graphs	Positioned nodes, directed edges and swimlanes	Graphs
`Form`	`panel.form`	Property editor for the current selection	Selections and the properties panel

Menus in the top bar, settings forms and value editors are rendered by the shell too, from declarations only — see Plugin settings and Value types.