pulled store art never goes into the app repo: art pull --write, init and onboard add the renders folder (relative to the repo root, e.g. /store/renders/) to the repo's .gitignore when git check-ignore says it is not ignored yet, with one line saying so; tests

cli/lib/git-ignore.ts

@@ -0,0 +1,28 @@
+// Keep a folder out of the app's git repo: store art pulled from the stores (and renders) is never committed.
+import { appendFileSync, existsSync, readFileSync, realpathSync, writeFileSync } from 'node:fs';
+import { spawnSync } from 'node:child_process';
+import { join, relative, sep } from 'node:path';
+
+const git = (cwd: string, args: string[]) => spawnSync('git', args, { cwd, encoding: 'utf8', timeout: 15_000 });
+
+/** When `dir` is inside a git repo and not ignored yet, adds `/<dir relative to the repo root>/` to the repo root's
+ *  .gitignore. Returns the line added, or null (no repo, no git, already ignored). `dry`: only says what it would add. */
+export function ignoreInRepo(dir: string, comment: string, dry = false): string | null {
+  let probe = dir;
+  while (!existsSync(probe)) { const up = join(probe, '..'); if (up === probe) return null; probe = up; }
+  const top = git(probe, ['rev-parse', '--show-toplevel']);
+  if (top.status !== 0) return null;
+  const root = realpathSync(top.stdout.trim());
+  let real: string;
+  try { real = realpathSync(probe) + dir.slice(probe.length); } catch { return null; }
+  const rel = relative(root, real).split(sep).join('/');
+  if (!rel || rel.startsWith('..')) return null;
+  if (git(root, ['check-ignore', '-q', `${rel}/`]).status === 0) return null;
+  const line = `/${rel}/`;
+  if (dry) return line;
+  const gi = join(root, '.gitignore');
+  const cur = existsSync(gi) ? readFileSync(gi, 'utf8') : '';
+  const add = `# ${comment}\n${line}\n`;
+  if (cur) appendFileSync(gi, `${cur.endsWith('\n') ? '' : '\n'}${add}`); else writeFileSync(gi, add);
+  return line;
+}