feat(templates): add the Payments paginating invoice preset

[DemchaAV]

Why

stripe-invoice is the richest bundle in the promotion queue and the first that
paginates: the design shows six service lines, a real billing month brings dozens,
and no built-in invoice preset flows today.

It is also the first bundle whose source carries a real company's identity, so this PR
is the pattern for the thirteen like it: the layout is ported in full, the identity
is not.

What

invoice.presets.PaymentsInvoice on the existing StructuredInvoiceData model.
Split as the family is: PaymentsInvoice routes, PaymentsStyles holds the tokens,
PaymentsText the figure formatting, and Masthead / Parties / Lines /
Settlement / Closing / Widgets / Icons draw.

De-branded, surgically

The bundle's branding turned out to sit in its data and in exactly one asset:

• brand-lockup.svg was the real Stripe wordmark (logos:stripe). Not ported. The
  preset reserves the design's measured 136 × 55.3 px lockup box and fills it from
  InvoiceBrand — a logo drawn to that height, or the brand's name as a wordmark. The
  templates artifact carries no mark of its own.
• The other twelve glyphs are stock Material and Lucide icons; only their token names
  were product-flavoured (item-atlas, item-radar, item-terminal), so they are
  renamed to what they draw: globe, shield, mobile.
• The legal entity, the product names and the note text were always data. The shipped
  sample is neutral.

It flows

The table's header repeats on every page it reaches, a continuation page reserves a
deeper bottom margin than page one, and every page carries its number — a financial
record that runs over has to make a missing page detectable.

One column, not five. The design shows an outer box and a rule between rows with no
interior verticals, which is exactly the topology a single-column table draws: a cell
strokes all four of its own edges and a one-column table has no interior vertical. The
five columns are a row inside each cell. Built the other way round — the box from a
stroked section wrapped round the table — every continuation page would end in an empty
bordered strip, because a section's box fills its page fragment rather than hugging its
rows.

The locale is stated, never inherited

Both the grouping of a number and the symbol for a currency code change with the locale
— USD is $ in English and US$ in the root locale — so a preset that let the JVM
decide would render a different sheet on a different machine and its baselines would
move with the machine rather than with the design. PaymentsText pins Locale.ENGLISH.

Tests

• Pixel parity against the bundle: 5 060 of 2 173 720 differing pixels, and the heat
  map has exactly one band — x 63..198, y 46..102, which is the lockup box measured
  off the design (63..198, 46.8..101.2). The diagonal band, the title, the issuer
  block, the metadata grid and its divider, both parties, all six marked table rows,
  the payment card, the totals, the due panel, the notes, the footer rule and both
  footer cells are pixel-identical; 177 layout nodes against the bundle's 177. The
  only thing that differs is the mark deliberately not shipped, and it differs inside
  its own box without moving anything around it.
• The bundle also freezes to 0 against its own published preview on both its pinned
  engine (2.2.2) and 2.2.3-SNAPSHOT, so there is no engine drift to account for.
• PaymentsInvoiceSmokeTest — 15 cases: the packaged marks, the unknown-mark data
  error, a line with no mark, the wordmark fallback, the currency named once and
  carried, the uppercased due line, a trunk prefix printed but not dialled, the support
  contacts as annotations, a missing ship-to, a missing note block, an empty document,
  and a thirty-line invoice that runs on, repeats its column names on page two and
  numbers its pages.
• PaymentsInvoiceLayoutSnapshotTest — exact geometry, one page.
• PaymentsInvoiceVisualParityTest — pixel baseline; recorded without disturbing any
  other baseline in the suite.
• Full reactor gate green:
  ./mvnw -B -ntp clean verify -pl :graph-compose-core,:graph-compose-render-pdf,:graph-compose-render-docx,:graph-compose-render-pptx,:graph-compose-templates,:graph-compose-testing,:graph-compose-qa,:graph-compose-coverage -am
• The showcase gains invoice-payments-v2; assets/readme/examples/invoice-payments-v2.pdf
  is regenerated from the committed code.