fix(runtime): unmount written <Static> items to match Ink (G01) (#34)

* fix(runtime): unmount written <Static> items to match Ink (G01)

Ink's <Static> renders `items.slice(index)` and advances `index` to
`items.length` in a post-commit `useLayoutEffect`, so once an item has been
painted it is removed from the tree and its component unmounts. vue-tui kept
every Static item mounted forever: the component always mapped the full
`props.items`, and write-once was enforced only at flush time via a positional
`writtenCount` slice — the item components never tore down.

Now the <Static> component owns a `cursor` (Ink's `index`) and renders only
`items.slice(cursor)`. The renderer advances the cursor AFTER a commit has
painted the fresh items, via an `onWritten` callback registered on the host
static node — the vue-tui analogue of Ink's post-commit layout effect. This
ordering guarantees items are written before they are sliced out and unmounted,
so no item is ever lost or re-painted.

Write-once bookkeeping moved from a positional `writtenCount` to a
`writtenNodes` Set keyed by host-node identity. A single logical item expands to
several host nodes (the <Text>/<Box> plus empty text-leaf fragment anchors Vue
inserts), so a positional count mis-sliced once the cursor advanced; identity
tracking is anchor-agnostic. The shared `paintStaticNode` helper paints children
not yet in the set, records them, prunes unmounted entries, then fires
`onWritten`; render.ts, render-to-string.ts and flushStatic all use it.

Make the cursor mirror Ink fully so it can DECREASE, not just increase.
`onWritten` now SETS the cursor to items.length (was max-with-current), and a
length watch lowers it on shrink — needed because a shrink that leaves the
already-sliced children empty produces no host mutation, hence no commit/
onWritten to re-sync. Without this, [A,B] (cursor→2) → [A] → [A,C] sliced(2)=[]
and silently dropped C. paintStaticNode now always prunes and calls onWritten
(even on empty commits), painting only when there are fresh children.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* chore(parity): ledger — G01 pr-open, reconcile G12 merged

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

packages/runtime/src/render.ts

@@ -21,8 +21,8 @@ import { attachYoga, detachYoga } from "./host/yoga.ts";
 import { buildNodeOps } from "./host/node-ops.ts";
 import { createCommitScheduler } from "./scheduler.ts";
 import { createAnimationScheduler } from "./animation-scheduler.ts";
-import { paint, paintIsolated } from "./paint/paint.ts";
-import { findStatics } from "./paint/static-channel.ts";
+import { paint } from "./paint/paint.ts";
+import { findStatics, paintStaticNode } from "./paint/static-channel.ts";
 import { createFrameWriter } from "./io/frame-writer.ts";
 import { bsu, esu, shouldSynchronize } from "./io/write-synchronized.ts";
 import {
@@ -550,13 +550,10 @@ export function createApp(root: Component, rootProps?: RootProps | null): TuiApp
       const w = resolveSize(stdout).columns;
       let staticOutput = "";
       for (const stat of findStatics(tuiRoot)) {
-        const fresh = stat.children.slice(stat.writtenCount);
-        if (fresh.length === 0) continue;
-        const staticFrame = paintIsolated(fresh, w, stat);
+        const staticFrame = paintStaticNode(stat, w);
         if (staticFrame.length > 0) {
           staticOutput += staticFrame + "\n";
         }
-        stat.writtenCount = stat.children.length;
       }
       const hasStaticOutput = staticOutput !== "" && staticOutput !== "\n";
       if (hasStaticOutput) {