What

Adds a dedicated Compositions guide — the concept other frameworks call "components," documented under Via's own vocabulary. Closes the long-standing gap where the composition model was scattered across Getting started, the glossary, and Actions & lifecycle with no page of its own.

Contents

• Nesting — a child is an exported struct field whose pointer has View; Mount folds its state in by reflection, with automatic per-instance isolation via field-prefixed wire keys (A.count, B.count).
• One tree, one render — the tree is allocated once per tab; the framework drives only the root; children are orchestrated by the parent; whole-tree top-down re-render + morph.
• Passing props — the blessed model: props are View parameters (compiler-checked, reactive by re-render). Event handlers are props too.
• Per-instance initial state — seed in the parent's OnInit via .Write(ctx, …), with a verified caveat: never reassign a child by value (binding is by-address before OnInit, so a struct-literal reassign zeroes slot/key — the value paints once but client bindings go dead and updates mis-route).
• Events (child → parent) — forward through a root action method, since actions dispatch by root method name.

Nav / supporting edits

• New page at Guides → nav_order 2 (after Actions & lifecycle); bumps Rendering/Routing/File uploads/Plugins by one.
• Glossary Composition entry now links to the page.

Docs-only; go build ./... green.