feat(documents)!: unify offers and issued orders end to end

One coherent pass over the two sibling document models, driven by a 3-lens
1:1 scan (~60 divergences inventoried) + user decisions. Migration adds
issued_orders.locked_by/locked_at and the issued_order_sections table
(mirror of scope_sections; applied to dev + test DBs).

Issued orders gained (offers as reference implementation):
- rich-text SECTIONS with CZ/EN titles, rendered on their own PDF page in
  the PO template's red style (shared DocumentSectionSchema, one-transaction
  create/update incl. items - fixes a torn-write bug)
- edit LOCKING (lock/heartbeat/unlock routes, 423 + holder name, 30s TTL =
  3 missed 10s heartbeats; locked_by enrichment on detail)
- archived-PDF serving: GET /:id/file reads the NAS copy (new
  readIssuedByNumber sweep) with live-render fallback + re-archive; offers'
  /file got the same fallback (kills the 'ulozte nabidku' dead end)
- NAS cleanup on delete, in-tx po_number uniqueness (409), collision-advancing
  number previews (also invoice previews), PUT returns assigned po_number

Offers hardened (issued as reference):
- VALID_TRANSITIONS enforced (no more numberless 'ordered' offers; invalidate
  follows the table; order creation only from active offers) +
  valid_transitions on detail
- explicit 400 instead of silent edits outside draft/active (mirrored on
  issued: explicit 400 replaced silent drops)
- customer existence check + Number(null)->0 clear bug fixed; delete of a
  linked offer -> 409 instead of P2003 500; error-token convention; Zod caps
  DB-aligned (desc 500/unit 20/number 50/project_code 100, isoDateString
  dates, ints for positions); audit old/new values + koncept fallbacks;
  list id tiebreaks; stats include trimmed; NAS delete dedupe

Frontend unification (6 new shared modules):
- components/document/{DocumentItemsEditor,SectionsEditor,LockBanner}
- hooks/{useDocumentLock,useUnsavedChangesGuard,useDocumentPdf(+list variant)}
- OfferDetail 1940->1100 lines, IssuedOrderDetail 1400->980: headline-only
  document number (form field removed), one form layout/readonly convention,
  view-permission opens read-only everywhere (issued's editable-for-viewers
  hole closed), server-driven transition buttons, dirty guard + Enter submit
  on both, useApiMutation everywhere (new opt-in envelope mode), fixed
  infinite spinner on failed detail fetch, draft PDFs hidden (no number yet)
- lists: supplier filter + count line on issued, Mena column dropped + mono
  numbers on offers, shared hardened per-row PDF flow (spinner, double-click
  guard, 401 close, blob cleanup), proper Czech quotes, real CTA empty
  states, query-lib cleanups (["offers","customers"] key, typed list rows,
  shared CurrencyAmount, retry:false on details)
- pdf-shared.ts: one escapeHtml/cleanQuillHtml(strict)/formatNum(NBSP)/
  formatCurrency/formatDate for all four PDF routes; offer PDF keeps its
  monochrome look (fractional qty fix: 1.5 no longer prints as 2); issued
  PDF language now comes from the document column

+49 tests (suite 364 -> 413). Each stage passed an independent review; final
cross-stage integration review verified the FE<->BE contracts.

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

src/routes/admin/invoices-pdf.ts

@@ -2,12 +2,18 @@ import { FastifyInstance } from "fastify";
 import QRCode from "qrcode";
 import prisma from "../../config/database";
 import { requirePermission } from "../../middleware/auth";
-import { localDateCzStr } from "../../utils/date";
 import { nasInvoicesManager } from "../../services/nas-financials-manager";
 import { htmlToPdf } from "../../utils/html-to-pdf";
 import { getRate } from "../../services/exchange-rates";
 import { localDateStr } from "../../utils/date";
 import { parseId, success } from "../../utils/response";
+import {
+  formatDate,
+  formatNum,
+  escapeHtml,
+  cleanQuillHtml,
+  buildQuillIndentCss,
+} from "../../utils/pdf-shared";
 import createDOMPurify from "dompurify";
 import { JSDOM } from "jsdom";
 
@@ -16,62 +22,6 @@ const DOMPurify = createDOMPurify(window);
 
 /* ── Helpers ─────────────────────────────────────────────────────── */
 
-function formatDate(date: Date | string | null | undefined): string {
-  if (!date) return "";
-  const d = new Date(date);
-  if (isNaN(d.getTime())) return String(date);
-  return localDateCzStr(d);
-}
-
-function formatNum(n: number, decimals = 2): string {
-  const abs = Math.abs(n);
-  const fixed = abs.toFixed(decimals);
-  const [intPart, decPart] = fixed.split(".");
-  const withSep = intPart.replace(/\B(?=(\d{3})+(?!\d))/g, "\u00A0");
-  const result = decPart ? `${withSep},${decPart}` : withSep;
-  return n < 0 ? `-${result}` : result;
-}
-
-function escapeHtml(str: string | null | undefined): string {
-  if (!str) return "";
-  return str
-    .replace(/&/g, "&amp;")
-    .replace(/</g, "&lt;")
-    .replace(/>/g, "&gt;")
-    .replace(/"/g, "&quot;");
-}
-
-function cleanQuillHtml(html: string | null | undefined): string {
-  if (!html) return "";
-  let s = html;
-  s = s.replace(
-    /<(script|iframe|object|embed|style|link|meta|base|form|input|textarea|button|select|svg|math)[^>]*>[\s\S]*?<\/\1>/gi,
-    "",
-  );
-  s = s.replace(
-    /<(script|iframe|object|embed|style|link|meta|base|form|input|textarea|button|select|svg|math)[^>]*\/?>/gi,
-    "",
-  );
-  s = s.replace(/\s+on\w+\s*=\s*("[^"]*"|'[^']*'|[^\s>]*)/gi, "");
-  s = s.replace(/\s+on\w+\s*=\s*[^\s>]*/gi, "");
-  s = s.replace(
-    /href\s*=\s*["']?\s*(javascript|data|vbscript)\s*:[^"'>\s]*/gi,
-    'href="#"',
-  );
-  s = s.replace(
-    /src\s*=\s*["']?\s*(javascript|data|vbscript)\s*:[^"'>\s]*/gi,
-    'src=""',
-  );
-  s = s.replace(/(&nbsp;)/g, " ");
-  s = s.replace(/\s+style\s*=\s*("[^"]*"|'[^']*'|[^\s>]*)/gi, "");
-  let prev = "";
-  while (prev !== s) {
-    prev = s;
-    s = s.replace(/<span([^>]*)>(.*?)<\/span>\s*<span\1>/gs, "<span$1>$2");
-  }
-  return s;
-}
-
 interface AddressResult {
   name: string;
   lines: string[];
@@ -535,13 +485,7 @@ export default async function invoicesPdfRoutes(
           : "";
 
         // Quill indent CSS
-        let indentCSS = "";
-        for (let n = 1; n <= 9; n++) {
-          const pad = n * 3;
-          const liPad = n * 3 + 1.5;
-          indentCSS += `  .ql-indent-${n} { padding-left: ${pad}em; }\n`;
-          indentCSS += `  li.ql-indent-${n} { padding-left: ${liPad}em; }\n`;
-        }
+        const indentCSS = buildQuillIndentCss();
 
         const html = `<!DOCTYPE html>
 <html lang="${escapeHtml(lang)}">