feat(print): add paged-media-safe document output

src/printStyles.test.ts

@@ -0,0 +1,56 @@
+import { readFileSync } from 'node:fs';
+import { resolve } from 'node:path';
+
+import { describe, expect, it } from 'vitest';
+
+const styles = readFileSync(resolve(process.cwd(), 'src/styles.css'), 'utf8');
+
+/** Match one CSS rule body for an exact selector within the shipped stylesheet. */
+function ruleBody(selector: string): string {
+  const escaped = selector.replace(/[.*+?^${}()|[\]\\]/gu, '\\$&');
+  const match = styles.match(new RegExp(`${escaped}\\s*\\{([^}]*)\\}`, 'u'));
+  if (!match?.[1]) throw new Error(`Missing CSS rule for ${selector}`);
+  return match[1];
+}
+
+describe('print stylesheet contract', () => {
+  it('defines an explicit paged-document print media boundary', () => {
+    expect(styles).toMatch(/@media\s+print\s*\{/u);
+  });
+
+  it('removes screen-only clipping and interactive chrome from printed output', () => {
+    const printIndex = styles.indexOf('@media print');
+    expect(printIndex).toBeGreaterThan(-1);
+    const printStyles = styles.slice(printIndex);
+
+    expect(printStyles).toMatch(
+      /\.cwl-toolbar[\s\S]*\.cwl-collaboration-status[\s\S]*\.collaboration-cursor__caret[\s\S]*\.collaboration-cursor__label[\s\S]*\{[^}]*display:\s*none\s*!important\s*;/u,
+    );
+    expect(printStyles).toMatch(
+      /\.cwl-editor__surface\s*\{[^}]*overflow(?:-y)?:\s*visible\s*;[^}]*max-height:\s*none\s*;/u,
+    );
+    expect(printStyles).toMatch(
+      /\.cwl-editor\s*\{[^}]*overflow:\s*visible\s*;[^}]*border:\s*0\s*;/u,
+    );
+  });
+
+  it('does not print placeholder UI and keeps document blocks page-safe', () => {
+    const printIndex = styles.indexOf('@media print');
+    expect(printIndex).toBeGreaterThan(-1);
+    const printStyles = styles.slice(printIndex);
+
+    expect(printStyles).toMatch(
+      /\.cwl-editor__content \.is-editor-empty:first-child::before\s*\{[^}]*content:\s*none\s*;/u,
+    );
+    expect(printStyles).toMatch(/break-inside:\s*avoid\s*;/u);
+    expect(printStyles).toMatch(/break-after:\s*avoid\s*;/u);
+    expect(printStyles).toMatch(/orphans:\s*3\s*;/u);
+    expect(printStyles).toMatch(/widows:\s*3\s*;/u);
+  });
+
+  it('keeps authored links distinguishable independently of color', () => {
+    expect(ruleBody('.cwl-editor__content a')).toMatch(
+      /text-decoration:\s*underline\s*;/u,
+    );
+  });
+});