Add the Monolith and Cobalt Stripe templates

Standalone layouts for Canva 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/03-monolith.md

@@ -139,3 +139,20 @@ Voiced fields with no Canva slot, and where they go:
 ## Similarity to other templates
 
 Structurally this is the closest of the three to the existing in-app InvoiceDocument: a title with a meta stack, rule dividers, a ruled table with a heavy top rule, right-hand totals with a rule above Total, and bank details at bottom left. It is also close to format.pdf/4.pdf (rules, a column-header row with a rule, right-hand totals). It is the cheapest to build, as a restyle of the existing component: Poppins, a 60pt auto-fit title, 1.5pt table rules, centred numbers and a two-column footer. Within the set, 7 and 11 share the big Poppins Bold INVOICE with the brand at top right; 3 is the monochrome, rules-only variant.
+
+## Implementation notes
+
+Built as `src/pdf/templates/monolith/`: a standalone template (`tokens.ts` the type roles and Canva distances, `plan.ts` the pure planner, `Layout.tsx` the body, `monolith.tsx` the definition), on the shared blocks and the `AccentRule` decor primitive. Measured against `3.pdf` with `npm run templates:compare -- monolith` (`/tmp/invoice-c6a/compare-monolith.png`, left Canva, right ours; `--numbers` prints the baselines).
+
+**Matches the design (measured, A4, no due date so the stack is the design's three lines):** INVOICE origin x 50.7 with its baseline at 96.0 (Canva 96.2); the vendor name, date and INVOICE NO. lines at baselines 63.7 / 84.7 / 105.7 with their right edge at x 560.3 (Canva 560.6); BILLED TO at baseline 153.0 and x 35 (Canva 153.0, 34.4); client lines at 178.1 with the 17.25 pitch; Poppins 400/500/700 at the design's sizes (60.02 / 14.5 / 12.5 / 10.5), black only (a test scans the sources for any other colour); 0.75 pt rules, the table between two 1.5 pt rules around a 39.3 pt header; the totals block 215.5 pt wide with centred labels, a 0.75 pt rule over Total and the 23 pt row pitch; the footer grid with its 114 pt label column and the colon column at x 149; the vendor column at x 395.
+
+**The logo.** The slot is the text-only "CAVEIN" placeholder (46.8 x 9 pt), so the logo is fitted to its 160 x 28 pt allowance, right-anchored, and the brand zone of the right-hand stack reserves the logo's whole box: the date and number lines are laid out under it, never over it (the earlier contact sheet showed a 28 pt logo covering the date line). A wordmark replaces the vendor name, a mark keeps it to its left, a tall logo is held to 28 pt, and with no logo the vendor name is printed in Bold 12.5 at the design's position. The zone is the `SUPPLIER_ID` box and the date and number lines the `META_ID` box, so the harness proves they do not meet.
+
+**Intentional deviations, and why:**
+- **Title.** The design's 60 pt is shrunk (to 30 pt at the least) when the right-hand stack leaves less than the title needs: TAX INVOICE comes out at about 51 pt on A4, and a long invoice number shrinks first (IdText) before the title does.
+- **Right-hand stack.** The design's three lines plus a "Due:" line (Regular 12.5) when the invoice has a due date, and a red CANCELLED line on a cancelled one. The rule under it follows the stack, so an invoice with a logo or a due date starts 13 to 34 pt lower than the design.
+- **Supplier identifiers.** The design's empty band under the client holds a SUPPLIER heading with the GSTIN (through `Slot.Gstin`) and PAN, in the footer's right-hand column x. They are on page 1 whatever the length of the invoice. The supplier's address, phone and e-mail are the footer's vendor block, as in the design, so on a multi-page invoice they appear on the last page only.
+- **Table.** Numbers are right-aligned with a 10 pt pad (the design centres them; the doc's recommendation) except QTY, which stays centred; the cells of a row share one baseline (Canva's description and numbers are 7 pt apart); the rate's unit is `/hr` or a second line, HSN/SAC a 10 pt sub-line. Row padding is 16 pt for up to 3 rows, 12 for up to 5 and 8 beyond, then the elastic gaps take over.
+- **Elastic gaps.** The 88 pt band under the client (down to 24), the row padding (down to 6), the gaps above BILLED TO and under the client block (down to 14) and the two gaps in the footer (down to 8) give back Letter's missing 50 pt, and the overflow of an invoice that is a little too long for one page. A 2-item tax invoice with a bank block fits one A4 page that way; with 3 rows and a signature image the closing block moves to page 2 (the items and totals stay together on page 1).
+- **Amount in words and reverse charge** are the totals' left column (Medium 10.5, x 35..329). **Notes** and the **signature** (an image up to 150 x 45, or the signatory name and designation and the computer-generated line) form the band above the footer's top rule; notes taller than 110 pt flow as their own block before the closing.
+- **Footer position.** The closing block ends 24 pt above the "Generated with Voiced" line, so its bottom rule is at y 804 where Canva's is at 812.