Add the Monolith and Cobalt Stripe templates

Standalone layouts for reference templates 3 and 8, with the user's logo sized to the
placeholder box, a CapRule decor primitive, optional TableRows rule/heading options,
and a separate 1..45-row sweep test file.

docs/templates/08-cobalt-stripe.md

@@ -140,3 +140,19 @@ No raster XObjects. Everything is vector shapes plus live text.
 - No near-duplicate in the set. It is the only template with cobalt bars, zebra rows and a swoosh logo. It shares the 'Studio Shodwe' placeholder copy with 7 and 11, but the layout is unrelated.
 - Shared-component candidate: the icon contact footer (phone/email/address) also appears in 2, 9 (circled icons) and 12/13. The zebra rows loosely echo 1 (grey zebra) and 12/13 (pill rows).
 - Does not resemble the in-app InvoiceDocument.tsx (closest in the set is 3.pdf), or format.pdf / 4.pdf.
+
+## Implementation notes
+
+Built as `src/pdf/templates/cobalt/`: a standalone template (`tokens.ts` the type roles, palette and reference distances, `plan.ts` the pure planner, `Layout.tsx` the body, `cobalt.tsx` the definition) on the shared blocks, the `CapRule` decor primitive (a grey round-capped rule with accent segments, one static Svg) and the Carbon icon paths. Measured against `8.pdf` with `npm run templates:compare -- cobalt-stripe` (`/tmp/invoice-c6a/compare-cobalt-stripe.png` and `-nologo.png`, left reference, right ours; `--numbers` prints the baselines).
+
+**Matches the design (measured, A4, the 8-row sample without GST data):** vendor name baseline 74.5 (reference 74.6) at x 59.5; INVOICE origin x 395.4 and baseline 87.2 (395.6 / 87.3), tracked +0.043 em with its ink ending on the right edge; the rule text baseline 117.1 and the header rule centred on y 113.8 with its sky accent at the left; "Billed to :" 173.8, the client name 195.8 and the first contact line 219.8 (173.8 / 195.9 / 219.9); "Invoice no" and the date at 174.8 / 194.0 (175.2 / 194.4); the table bar 20.76 pt tall at y 292 with its heading baseline at 304.6 (304.7), the five columns at 24.9 / 84.9 / 105.4 / 89.3 pt and rows of 17.82 pt, the first row baseline 325.7 (325.2); the price ends 31.7 pt inside its column (x 414.7, reference 414.9) and the total 3.1 pt inside the edge; Sub Total at 477.0 with its label at x 363.5 (477.0 / 363.7); the GRAND TOTAL bar 214.5 x 20.76 beside the PAYMENT METHOD bar 133.8 wide, both cobalt; the bank lines 541.0 (reference 561.8 less its second tax row); every colour is one of the design's (a test scans the sources).
+
+**Intentional deviations, and why:**
+- **Script signature.** Not reproduced (BD Script is licensed by reference). The signature slot is the user's image (up to 36 pt tall, right-aligned, 5.5 pt inside the edge) or, without one, the signatory name and designation plus "Computer-generated invoice; no signature is required."
+- **Header content.** The tagline under the name is the supplier's GSTIN (through `Slot.Gstin`, in caps) and the text at the end of the rule is the PAN. A logo goes in the measured slot: a mark (at most 34.25 pt square) keeps the name and tagline beside it; a wordmark (at most 181.5 x 34.25 pt, left-anchored) replaces the name and the tagline moves under it, which makes the header 13 pt taller. With no logo the name starts at the margin. The rule row follows the header, so it is never nearer than 6 pt to it.
+- **Right-hand column.** "Invoice no : N" and the date as in the design, plus "Due date" and "PO" lines; a red CANCELLED line on a cancelled invoice. The client's GSTIN and place of supply follow the address in the grey 10 pt lines, whose pitch is 17.5 pt (reference 19.2) so longer blocks fit.
+- **Table.** HSN/SAC is an 8.5 pt grey sub-line under the description (no slot in the design), which makes a row 11.5 pt taller; wrapped descriptions grow the row, and the zebra fill and the 1.5 pt light-blue separators are per cell, so they grow with it. The rate's unit is `/hr` or a second line. `TableRows` gained two additive options for this template: `innerRules` (separators between the columns only, no outer edge and no top rule) and `headAlign` (the heading centred over a left-aligned column).
+- **Totals.** "Sub Total :", Discount, Taxable Value and the CGST / SGST / IGST rows (labelled "CGST 9% :") end at the label column's right edge (x 417.4 of the design); the amount in words and the reverse-charge line sit under the GRAND TOTAL bar, right-aligned in 9.5 pt grey. The PAYMENT METHOD bar is level with the GRAND TOTAL bar as in the design whenever the invoice still fits its page that way; with a longer stack (a GST invoice has up to five rows against the design's two) it moves up beside the first row, which gives back up to the stack's height (104 pt for five rows), and the bank lines follow it.
+- **Closing.** The divider, "Thank you for business with us!" and the terms (the notes; taller than 110 pt they flow as a block of their own before the closing) at the left, the signature at the right, then the icon footer: the footer rule with accents at both ends, and phone, e-mail and address with Carbon icons (26 pt boxes, sky). The footer is part of the closing block, so it is on the last page only, not on every page, and everything in it is audited. The contacts keep their natural width at 32.5 pt apart; when they do not fit, the address wraps into what is left and the phone and e-mail shrink only if the address would get under 120 pt.
+- **Elastic gaps** (Letter, and A4 when a one-page invoice overflows by less than the slack): header to client (42 to 26 pt), client to table (30.5 to 16), last row to the totals (9.8 to 4), thank-you to terms (26 to 14) and terms to the footer rule (16 to 8). Type is never scaled.
+- **Margins.** 54.2 pt at the top (the INVOICE line box starts there so its baseline lands at 87.2), 59.55 at the sides and 35.5 plus the 24 pt footer reserve at the foot, which puts the icons' bottom 59.5 pt above the page foot as in the design.