Add Ledger and Band template families with decor primitives

Crimson Grid, Tangerine Ledger, Slate Band and Teal Swoosh are rebuilt from
the Canva PDFs with grid and band tables that survive page breaks,
full-bleed fixed bands, pennant tabs, gradient corner swooshes with
keep-outs, Carbon icon circles, and the user's logo in the measured slot
(knockout or white chip on the dark Slate band). Adds static Poppins
500-700 and Inter fonts. Thumbnails regenerated for all eight templates;
the item-count sweeps run in their own test file.

docs/templates/09-slate-band.md

@@ -128,3 +128,20 @@ No raster XObjects. Everything is vector shapes plus live text.
 - Near-duplicate: 10.pdf ('Liceria & Co.'). The body is identical: Date / Billed to / From, the full-bleed grey SERVICE-QTY-PRICE-TOTAL band, rule-separated rows, TOTAL with an accent dash, inline Payment method / Note. The header differs: teal/grey corner swoosh artwork instead of the slate and blue bands, a dark letter-spaced INVOICE on white, and NO. in the right column. 10 also has a 'Contact:' block instead of the icon footer. Build 9 and 10 as one component with header/decoration variants.
 - Shares Montserrat and letter-spaced uppercase INVOICE/headers with format.pdf (identical to 4.pdf), but the structure is different.
 - Does not resemble the in-app InvoiceDocument.tsx; the closest in the set is 3.pdf.
+
+## Implementation notes
+
+Built as `src/pdf/templates/band/` (one family component, `Layout.tsx`, shared with Teal Swoosh; tokens in `slate.tsx`, planning in `plan.ts`) on the decor primitives in `src/pdf/decor/`. Measured against `9.pdf` with `npm run templates:compare` (`/tmp/invoice-c4/compare-slate-band.png`, left Canva, right ours; also `-nologo` and the logo variants).
+
+**Matches the design (measured, A4):** dark band 0-103.5, blue band to 157.35 (53.8 tall), INVOICE in Montserrat 800 30 pt with 0.224 em tracking at x 59.5; the name and 'NO.' baseline at 74.7 (Canva 74.4 / 74.8), the number right-aligned to the content edge; Date row baseline 193.4 (label and value share it); party heading to first line 21.3 pt; header band 58.3 tall and full bleed; table text at x 69.4 (the 9.8 pt inset) with 2.25 pt #C1C5CE rules from 69 to 526; TOTAL with the 41.85 x 3 pt dash on its baseline; the footer rule 86.7 pt above the page bottom.
+
+**Intentional deviations, and why:**
+- **Bands.** Both are first-page decor inside `FirstPageHeader`, full bleed from the page edges (so they also fill Letter and any margin preset); their heights follow the flow (page top margin + logo row + gap), so they stay glued to the logo row whatever the preset. They overlap by half a point so no viewer shows a seam.
+- **Logo (dark surface).** The slot is the measured 25 x 31 mark / 99 x 31 lockup. A logo with alpha uses its white knockout; one without alpha sits on a white rounded chip (4 pt padding) drawn as decor behind it. A wordmark replaces the name; a mark keeps the vendor name beside it in white Medium 12.
+- **Number and due date.** 'NO. {number}' in the band; 'Due:' goes in the right column of the Date row (the From column), 'PO No:' under Date.
+- **Table.** SERVICE / QTY / PRICE / TOTAL with PRICE right-aligned (centred prices left a ragged edge); the HSN/SAC code is a 10 pt sub-line under the description; the rate unit is '/hr' on the same line or a second 10 pt line when it does not fit. Rows are 44 pt (padY 13.5 + the rule) instead of 52.5, the compact density the doc offers, so a Voiced invoice (longer supplier block, tax rows, words, bank) still fits a page; the header band keeps its 58.3 pt. Money columns are at least 55 / 95 / 105 pt and grow to their widest amount (a 12-digit amount does not overflow from 1 lakh up).
+- **Totals.** The design has only TOTAL. A right-anchored stack (SUBTOTAL, DISCOUNT, TAXABLE VALUE, CGST/SGST or IGST via `Slot.TaxRows`, tracked Bold 11 labels over Regular 12 amounts, 20 pt pitch) and a thin rule sit above the TOTAL row; the amount in words runs full width below it.
+- **Payment, note, signature.** 'Payment details:' is a label plus bank lines (the inline single value does not scale); the Note sits under it when it is at most 100 pt tall, else flows below the table; the signature (the user's image or the signatory name and the computer-generated line) is the right column.
+- **Footer.** Circled Carbon icons (phone, e-mail instead of the globe because Voiced has no website field, location) with 1.2 pt rings, drawn as static Svg decor on every page. Decor is not audited, so each text is fitted to one line (phone, e-mail) or two with an ellipsis (address); the full address is printed in the From block. The standard footer (name, 'Generated with Voiced', Page n of N) is added below the icons in grey 7 pt.
+- **Margins.** Top 55.75 (the logo top), sides 59.55, bottom floor 20 plus a 79 pt reserve: the flow ends at least 99 pt above the page bottom (rule 86.7 + 12), on every preset.
+- **Letter.** The 49.9 pt deficit comes out of the band's bottom padding (16.5 to 8), the gaps to the date row, parties and table, and the gap above the totals (54 pt of slack); type, rows and the header band are not scaled.