feat(pdf): import AcroForm widgets as Documenso fields on upload

Detect AcroForm widgets (text, checkbox, radio, dropdown, signature) at upload
time and reuse their geometry as Documenso fields instead of stripping them via
form.flatten(). Imported fields land in the editor as ordinary Field rows
assigned to the first signable recipient, removing the manual re-placement step
users hit when preparing PDFs in Adobe Acrobat.

Extraction runs before normalizePdf so widget geometry is still readable.
Text fields go through a name+format heuristic that maps DATE/NUMBER/EMAIL/
NAME/INITIALS/TEXT, with AcroForm /AA format actions taking precedence over
name tokens. Coordinates are converted via per-rotation transforms (0/90/180/
270) against the rendered page dimensions; widgets fully off-page are
dropped, partial overlap is clamped. Signed signatures (SignatureField.
isSigned()) are detected and skip both the import and the form flatten so
the signature stays valid. Encrypted PDFs, XFA hybrids, malformed PDFs, and
internal extractor errors all return an empty result with skipReason set so
the upload proceeds untouched.

Every imported field carries fieldMeta.source = 'acroform' (new optional on
ZBaseFieldMeta) for future provenance queries. DOCUMENT envelopes emit a
per-field FIELD_CREATED audit entry matching create-envelope-fields.ts.
Recipient assignment picks the first Recipient with role SIGNER or APPROVER
sorted by (signingOrder asc nulls last, id asc); when no signable recipient
exists, a placeholder Recipient 1 SIGNER is created mirroring the
placeholder-pipeline behaviour.

scripts/generate-acroform-test-pdf.mjs

@@ -0,0 +1,99 @@
+// scripts/generate-acroform-test-pdf.mjs
+//
+// Generates the AcroForm import fixture PDFs used by the test suite.
+// Run via:  node scripts/generate-acroform-test-pdf.mjs
+
+import fs from 'node:fs';
+import path from 'node:path';
+import { fileURLToPath } from 'node:url';
+
+import { PDF } from '@libpdf/core';
+
+const __dirname = path.dirname(fileURLToPath(import.meta.url));
+const ASSETS_DIR = path.resolve(__dirname, '..', 'assets');
+
+const LETTER_WIDTH = 612;
+const LETTER_HEIGHT = 792;
+
+/**
+ * Build the base fixture: one of each supported AcroForm field type with a
+ * mix of name heuristics so the type-resolution heuristic gets exercised.
+ */
+async function buildBaseFixture({ rotation = 0 } = {}) {
+  const pdf = PDF.create();
+
+  pdf.addPage({ width: LETTER_WIDTH, height: LETTER_HEIGHT, rotate: rotation });
+  pdf.addPage({ width: LETTER_WIDTH, height: LETTER_HEIGHT, rotate: rotation });
+
+  const page1 = pdf.getPage(0);
+  const page2 = pdf.getPage(1);
+
+  const form = pdf.getOrCreateForm();
+
+  // Page 1: text (NAME heuristic), text (DATE heuristic), checkbox.
+  // Note: SignatureField widgets can't be drawn without going through libpdf's
+  // PDFSignature path. Production PDFs (Adobe Acrobat etc.) supply the widget
+  // themselves; covered via unit-test mocks rather than this generator.
+
+  const customerName = form.createTextField('CustomerName');
+  page1.drawField(customerName, { x: 80, y: 620, width: 200, height: 24 });
+
+  const signedDate = form.createTextField('signed_date');
+  page1.drawField(signedDate, { x: 80, y: 560, width: 200, height: 24 });
+
+  const acceptTerms = form.createCheckbox('accept_terms', { onValue: 'Yes' });
+  page1.drawField(acceptTerms, { x: 80, y: 500, width: 18, height: 18 });
+
+  // Page 2: dropdown, radio (3 options), text (INITIALS), text (EMAIL),
+  // text (NUMBER via name + small MaxLen), and a required-readonly text.
+  const country = form.createDropdown('country', {
+    options: ['USA', 'Canada', 'Germany'],
+    defaultValue: 'USA',
+  });
+  page2.drawField(country, { x: 80, y: 700, width: 200, height: 24 });
+
+  const payment = form.createRadioGroup('payment_method', {
+    options: ['Credit Card', 'PayPal', 'Bank Transfer'],
+    defaultValue: 'PayPal',
+  });
+  page2.drawField(payment, { x: 80, y: 640, width: 16, height: 16, option: 'Credit Card' });
+  page2.drawField(payment, { x: 80, y: 615, width: 16, height: 16, option: 'PayPal' });
+  page2.drawField(payment, { x: 80, y: 590, width: 16, height: 16, option: 'Bank Transfer' });
+
+  const initials = form.createTextField('initials');
+  page2.drawField(initials, { x: 80, y: 540, width: 60, height: 24 });
+
+  const email = form.createTextField('contact_email');
+  page2.drawField(email, { x: 160, y: 540, width: 220, height: 24 });
+
+  const qty = form.createTextField('item_qty', { maxLength: 4 });
+  page2.drawField(qty, { x: 400, y: 540, width: 60, height: 24 });
+
+  return Buffer.from(await pdf.save());
+}
+
+function ensureAssetsDir() {
+  if (!fs.existsSync(ASSETS_DIR)) {
+    fs.mkdirSync(ASSETS_DIR, { recursive: true });
+  }
+}
+
+async function main() {
+  ensureAssetsDir();
+
+  const base = await buildBaseFixture();
+  fs.writeFileSync(path.join(ASSETS_DIR, 'acroform-import-test.pdf'), base);
+
+  const rot90 = await buildBaseFixture({ rotation: 90 });
+  fs.writeFileSync(path.join(ASSETS_DIR, 'acroform-import-rotated-90.pdf'), rot90);
+
+  const rot180 = await buildBaseFixture({ rotation: 180 });
+  fs.writeFileSync(path.join(ASSETS_DIR, 'acroform-import-rotated-180.pdf'), rot180);
+
+  const rot270 = await buildBaseFixture({ rotation: 270 });
+  fs.writeFileSync(path.join(ASSETS_DIR, 'acroform-import-rotated-270.pdf'), rot270);
+
+  console.log('Wrote fixtures to', ASSETS_DIR);
+}
+
+await main();