Hover card DX

[benjaminleonard]

Pulls three useful things up from the docs site.

plainText(inlines) — flattens an inline AST to visible plain text, entity-decoded. Merges the app's inlineText + decodeEntities. The walk is coupled to the InlineNode union and the library owns the decision to leave numeric entities (’) in text nodes, so it should own resolving them on the way to plain text. The per-node switch is exhaustive with a never default — adding a node type is now a compile error here rather than a silent drop (the bug that motivated this: an app-side copy broke when the union gained raw). Helpful for something like a hover card or search section preview.

Block union fix — adds ListBlock, DListBlock, ListItemBlock, and Cell to the public Block union. items/cell shapes are now reachable without casting (block as { items?: … }).

findSection(blocks, id) — depth-first find-by-id over the block AST, descending through child blocks, list items, and table cells.

Canary: npm install @oxide/react-asciidoc@2.0.0-canary.bd2aad7