markup: digit-only attribute values pass check+build then blank the window at runtime

[donpark]

An attribute value that consists only of digits (e.g. placeholder="32") passes every build-time gate — native check (including the subset checker), native build, markup check --strict, markup dump — but the runtime view builder's value tokenizer aborts the whole view with expected text, leaving an empty window. No build-time diagnostic points at the cause; the app is blank and the only clue is a single startup log line.

Discovered in a real app: placeholder="32" on a bitrate text-field produced a blank window; changing the value to e.g. 32 rendered. Any all-digits attribute value triggers it.

Repro

From a clean native init app (TypeScript core), replace src/app.native with:

<column gap="12" padding="16">
  <text-field text="{value}" label="Digits placeholder" placeholder="32" />
</column>

src/core.ts (boilerplate, any valid Model works):

import { utf8Bytes } from "@native-sdk/core";

export interface Model {
  readonly value: Uint8Array;
}

export function initialModel(): Model {
  return { value: utf8Bytes("") };
}

export type Msg = { readonly kind: "noop" };

export function update(model: Model, _msg: Msg): Model {
  return model;
}

Build and run:

native build && ./zig-out/bin/<appname>

Expected: the text field renders with placeholder 32.

Actual: the window is blank. Stdout shows one line at startup and nothing else:

markup view failed to build (2:3): expected text

Control

The same file with placeholder="e.g. 32" builds, checks, and renders correctly (no markup view failed line). So the tokenizer treats an all-digit attribute value as a non-text token and fails; any non-digit prefix works around it.

Environment

• native 0.10.1 (064ca98), CLI reports native 0.10.1 (commit 064ca98, automation protocol 0x51f7889bbe3305e7)
• macOS 26.6.2 (arm64)
• Zig 0.16.0, Node v24.20.0

Notes

• Same bug family as @native-sdk/core/text fails the subset checker's integer proofs once TextEditState is a Model field #406 (numeric values tripping a validation layer while the other layers accept them), but different layer: this one is the runtime view builder's value tokenizer, and its failure mode is a silent blank window rather than a build error.
• Two layers disagree: the static parser/checker accept all-digit values, so the only failure signal is one runtime log line. Either the static checker should reject all-digit attribute values, or (better) the runtime tokenizer should accept them the way the static parser does.

[ctate]

@donpark Thanks for the issue! Fixed in #427