Function computePreviewTilePxFromWidth

renderer.js:611–620

* Fixed preview columns per size; tile dimension scales to fill row width. * S → 10 columns; M → 6 columns; L → 4 columns.

(availableWidth, horizontalGap = 2)

      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        prompt,
        imageUrl: imageUrl || null,
        model: modelName,
        authToken: puter.authToken || null
      })
    }).then(async (resp) => {
      const data = await resp.json().catch(() => ({}));
      if (!resp.ok) {
        const err = new Error(data.error || `Puter AI proxy error (${resp.status})`);
        if (data.code) err.code = data.code;
        throw err;
      }