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/views/AppSettings.tsx

@@ -19,6 +19,7 @@ import {
   TableRow,
   TextArea,
   TextInput,
+  Tile,
   Toggle,
 } from "@carbon/react";
 import { Add, Save, TrashCan } from "@carbon/icons-react";
@@ -33,6 +34,7 @@ import {
 } from "../lib/types";
 import { emailError, ifscError, panError, phoneError, vendorGstinError } from "../lib/validators";
 import { ImagePicker } from "../components/ImagePicker";
+import { LogoBranding } from "../components/LogoBranding";
 import DiagnosticsPanel from "../components/DiagnosticsPanel";
 
 const blankBank = (): BankAccount => ({
@@ -264,14 +266,6 @@ export default function AppSettings({
               onChange={(e) => set("signatoryDesignation", e.target.value)}
             />
           </Column>
-          <Column sm={4} md={8} lg={8}>
-            <ImagePicker
-              kind="logo"
-              label="Vendor logo"
-              value={form.logoPath}
-              onChange={(path) => set("logoPath", path)}
-            />
-          </Column>
           <Column sm={4} md={8} lg={8}>
             <ImagePicker
               kind="signature"
@@ -283,6 +277,18 @@ export default function AppSettings({
         </Grid>
       </section>
 
+      <section className="voiced-stack" style={{ marginBottom: "2.5rem" }}>
+        <h3>Branding</h3>
+        <Tile>
+          <LogoBranding
+            idPrefix="s"
+            value={form}
+            onChange={(patch) => setForm((prev) => ({ ...prev, ...patch }))}
+            disabled={busy}
+          />
+        </Tile>
+      </section>
+
       <section className="voiced-stack" style={{ marginBottom: "2.5rem" }}>
         <h3>Defaults</h3>
         <Grid narrow>