feat(theme): lime dark variant for illustration-2; tune github dark mark

- Add illustration-2.dark.svg — a clone of the light vector recolored from
  #9C7979 (rose) to #e6f59f (lime brand accent) — and wire it into SplitLayout
  via ThemedImage's optimistic dark source (falls back to light if absent).
- Adjust the github.dark.png dark-mode mark.

Author: yahyafakhroji

app/layouts/split.layout.tsx

@@ -1,7 +1,7 @@
 import { BrandLogo } from '@/components/brand-logo/brand-logo';
 import { ThemedImage } from '@/components/themed-image/themed-image';
 import type { BrandingTheme } from '@/modules/auth/types';
-import { assetUrl } from '@/utils/asset-url';
+import { assetUrl, darkAssetUrl } from '@/utils/asset-url';
 import { Avatar, AvatarFallback, AvatarImage } from '@datum-cloud/datum-ui/avatar';
 import { LinkButton } from '@datum-cloud/datum-ui/button';
 import { Icon } from '@datum-cloud/datum-ui/icons';
@@ -75,10 +75,11 @@ export default function SplitLayout({
                   object-contain keeps the line-art crisp/uncropped while it scales down into the
                   115px box. Design note (asset pending): replace with a vector (SVG) or AVIF source — a designer
                   asset is still needed; this raster is the only source that currently exists.
-                  Dark mode (#9C7979 rose line-art on the dark panel): the seam is wired — once
-                  /images/illustration-2.dark.svg exists, pass dark={darkAssetUrl('/images/illustration-2.svg')}. */}
+                  Dark mode swaps to illustration-2.dark.svg, recolored to the lime brand
+                  accent (#e6f59f); the dark source is optimistic and falls back to light if absent. */}
               <ThemedImage
                 light={assetUrl('/images/illustration-2.svg')}
+                dark={darkAssetUrl('/images/illustration-2.svg')}
                 alt=""
                 aria-hidden="true"
                 width={232}

app/modules/i18n/locales/en.po

@@ -437,7 +437,7 @@ msgstr "Phone sign-in isn't available — use your email or username."
 msgid "Please check your input and try again."
 msgstr "Please check your input and try again."
 
-#: app/layouts/split.layout.tsx:101
+#: app/layouts/split.layout.tsx:102
 msgid "Prefer a demo instead? Just <0>reach out</0>."
 msgstr "Prefer a demo instead? Just <0>reach out</0>."
 
@@ -598,7 +598,7 @@ msgstr "Something went wrong. Please try again."
 msgid "Start over"
 msgstr "Start over"
 
-#: app/layouts/split.layout.tsx:113
+#: app/layouts/split.layout.tsx:114
 msgid "Thanks,"
 msgstr "Thanks,"
 
@@ -688,7 +688,7 @@ msgstr "Use your security key to verify your identity."
 msgid "Username"
 msgstr "Username"
 
-#: app/layouts/split.layout.tsx:91
+#: app/layouts/split.layout.tsx:92
 msgid "Using Datum requires setting up a billing account, but to help you explore without cost, we add <0>$50 USD</0> in credit on signup."
 msgstr "Using Datum requires setting up a billing account, but to help you explore without cost, we add <0>$50 USD</0> in credit on signup."