Add Rust logo pipeline: trim, metrics, knockout and Branding settings

Logos (PNG, JPEG, WebP) are decoded, trimmed to their ink box, downscaled
to 1200 px and re-encoded as a content-addressed print PNG plus a white
knockout variant when the logo has alpha; aspect, ink density, mean colour
and kind (wordmark, mark, tall) are stored with the settings and frozen in
the issue snapshot. Legacy logos are derived at startup. The Arun P logo
PDF shrinks from 334 KB to 92 KB. Settings gains a Branding section with
white and dark previews and a business-name toggle (migration M5).

src/pdf/model/build.test.ts

@@ -12,6 +12,10 @@ const vendor: Settings = {
   vendorGstin: "",
   vendorStateCode: "29",
   logoPath: null,
+  logoOriginalPath: null,
+  logoKnockoutPath: null,
+  logoMeta: "",
+  logoIncludesName: "auto",
   signaturePath: null,
   defaultBankId: 1,
   defaultTaxRate: 18,
@@ -229,7 +233,17 @@ describe("cancelled and logo", () => {
     expect(make({ status: "draft" }).cancelled).toBe(false);
   });
   it("passes the logo and signature through, and keeps null when absent", () => {
-    const logo = { dataUri: "data:image/png;base64,AA==", width: 200, height: 40 };
+    const logo = {
+      dataUri: "data:image/png;base64,AA==",
+      width: 200,
+      height: 40,
+      aspect: 5,
+      density: 0.43,
+      kind: "wordmark" as const,
+      includesName: true,
+      hasKnockout: true,
+      knockoutDataUri: "data:image/png;base64,CC==",
+    };
     const m = make({}, {}, { logo, signatureDataUri: "data:image/png;base64,BB==" });
     expect(m.logo).toEqual(logo);
     expect(m.signature.dataUri).toBe("data:image/png;base64,BB==");

src/pdf/model/build.ts

@@ -11,9 +11,21 @@ import { sanitize, splitLines } from "./text";
 import { bankFromSnapshot, vendorFromSnapshot } from "./vendor";
 
 export interface LogoInput {
+  /** The trimmed print image. */
   dataUri: string;
+  /** Pixel size of `dataUri`. */
   width: number;
   height: number;
+  /** Width / height of the ink box. */
+  aspect: number;
+  /** Share of the box that is ink, 0 to 1. */
+  density: number;
+  kind: "wordmark" | "mark" | "tall";
+  /** The logo already carries the business name (the user's setting, resolved from Automatic). */
+  includesName: boolean;
+  /** A white-ink variant exists, for dark surfaces. */
+  hasKnockout?: boolean;
+  knockoutDataUri?: string;
 }
 
 export interface BuildInput {

src/pdf/model/vendor.ts

@@ -7,7 +7,15 @@ import type { BankAccount, Settings } from "../../lib/types";
 export function vendorFromSnapshot(snapshot: string | undefined, live: Settings): Settings {
   if (!snapshot) return live;
   try {
-    return { ...live, ...(JSON.parse(snapshot) as Partial<Settings>) };
+    const frozen = JSON.parse(snapshot) as Partial<Settings>;
+    // Snapshots from before the logo pipeline lack these keys; the live values describe a different logo.
+    return {
+      ...live,
+      logoKnockoutPath: null,
+      logoMeta: "",
+      logoIncludesName: "auto",
+      ...frozen,
+    };
   } catch {
     return live;
   }