refactor(website): split the hero terminal and the page components

HeroTerminal was a single 367-line component doing three separate jobs:
simulating the transfer queue, holding the per-search result sets, and
rendering. It is now useTransfers, useResults and useHeroDemo behind a
presentational component. The dead shellRef went with it.

The home, docs and install pages each returned one long JSX block; every
section is now a named component, so the page body reads as an outline.

The prerendered HTML is byte-identical for all five pages, and the extracted
transfer reducer matches the original over 200 ticks.

website/src/components/tui/use-results.ts

@@ -0,0 +1,77 @@
+import { useCallback, useEffect, useMemo, useRef, useState } from 'react'
+
+import { RESULTS, type ResultRow } from './data'
+
+type Results = Readonly<Record<string, readonly ResultRow[]>>
+
+/** Result sets per search, which row is selected, and what is marked or already queued. */
+export const useResults = (queue: (rows: readonly ResultRow[]) => void) => {
+  const [results, setResults] = useState<Results>(RESULTS)
+  const [activeId, setActiveId] = useState('s1')
+  const [selected, setSelected] = useState(0)
+
+  const resultsRef = useRef(results)
+  useEffect(() => {
+    resultsRef.current = results
+  }, [results])
+
+  const rows = useMemo(() => results[activeId] ?? [], [results, activeId])
+
+  const patch = useCallback(
+    (searchId: string, edit: (row: ResultRow, index: number) => ResultRow) => {
+      setResults((prev) => ({ ...prev, [searchId]: (prev[searchId] ?? []).map(edit) }))
+    },
+    [],
+  )
+
+  const queueFrom = useCallback(
+    (searchId: string, indexes: readonly number[]) => {
+      const current = resultsRef.current[searchId] ?? []
+      const picked = indexes
+        .map((i) => current[i])
+        .filter((row): row is ResultRow => row !== undefined && row.queued !== true)
+      if (picked.length === 0) return
+
+      const wanted = new Set(picked.map((row) => row.name))
+      patch(searchId, (row) =>
+        wanted.has(row.name) ? { ...row, queued: true, marked: false } : row,
+      )
+      queue(picked)
+    },
+    [patch, queue],
+  )
+
+  const mark = useCallback(
+    (row: number) => {
+      patch('s1', (r, i) => (i === row ? { ...r, marked: true } : r))
+    },
+    [patch],
+  )
+
+  const open = useCallback((id: string, next?: readonly ResultRow[]) => {
+    if (next) setResults((prev) => ({ ...prev, [id]: next }))
+    setActiveId(id)
+    setSelected(0)
+  }, [])
+
+  return {
+    rows,
+    activeId,
+    selected,
+    setSelected,
+    open,
+    mark,
+    queueFrom,
+    queueIndexes: (indexes: readonly number[]) => {
+      queueFrom(activeId, indexes)
+    },
+    toggleMark: (index: number) => {
+      patch(activeId, (row, i) =>
+        i === index && row.queued !== true ? { ...row, marked: row.marked !== true } : row,
+      )
+    },
+    markAll: (on: boolean) => {
+      patch(activeId, (row) => (row.queued === true ? row : { ...row, marked: on }))
+    },
+  }
+}