fix(pdf): Segoe UI everywhere + rich-text colors survive sanitization

- section/Quill overrides, footers and the shared header now lead with
  'Segoe UI' (installed on prod) instead of Tahoma (not installed — prod
  silently rendered sections and footers in Noto Sans, mismatching the
  Segoe UI body; dev previews showed real Tahoma and never matched prod)
- cleanQuillHtml no longer deletes ALL style attributes: color and
  background-color survive with strictly validated literal values (hex,
  rgb/rgba, keyword) so editor font colors finally reach the PDF; url(),
  expression() and every other declaration are still stripped — new test
  file pins both the kept colors and the attack vectors

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/__tests__/pdf-shared.test.ts

@@ -0,0 +1,44 @@
+import { describe, it, expect } from "vitest";
+import { cleanQuillHtml } from "../utils/pdf-shared";
+
+describe("cleanQuillHtml — inline-style whitelist", () => {
+  it("keeps Quill text and background colors", () => {
+    const html =
+      '<p><span style="color: rgb(230, 0, 0);">červeně</span> ' +
+      '<span style="background-color: #ffff00;">zvýrazněně</span> ' +
+      '<span style="color: #06c;">modře</span></p>';
+    const out = cleanQuillHtml(html);
+    expect(out).toContain('style="color: rgb(230, 0, 0)"');
+    expect(out).toContain('style="background-color: #ffff00"');
+    expect(out).toContain('style="color: #06c"');
+  });
+
+  it("drops every non-color style declaration", () => {
+    const out = cleanQuillHtml(
+      '<span style="position: fixed; color: red; font-size: 99px;">x</span>',
+    );
+    expect(out).toBe('<span style="color: red">x</span>');
+  });
+
+  it("drops unsafe color values (url, expression, quotes)", () => {
+    expect(
+      cleanQuillHtml('<span style="color: url(javascript:alert(1))">x</span>'),
+    ).toBe("<span>x</span>");
+    expect(
+      cleanQuillHtml('<span style="color: expression(alert(1))">x</span>'),
+    ).toBe("<span>x</span>");
+    expect(cleanQuillHtml("<span style='color: \"red\"'>x</span>")).toBe(
+      "<span>x</span>",
+    );
+  });
+
+  it("keeps stripping scripts, event handlers and js: URLs", () => {
+    const out = cleanQuillHtml(
+      '<p onclick="alert(1)"><script>alert(1)</script>' +
+        '<a href="javascript:alert(1)">x</a></p>',
+    );
+    expect(out).not.toContain("script");
+    expect(out).not.toContain("onclick");
+    expect(out).not.toContain("javascript:");
+  });
+});