fix(dashboard): show Stack Auth logo on left of rebrand modal (#1495)

## Summary

The Stack Auth → Hexclave rebrand modal added in
[#1493](https://github.com/hexclave/stack-auth/pull/1493) rendered the
**Hexclave** logo on both sides of its illustration instead of *Stack
Auth → Hexclave*.

## Root cause


[\`hexclave-rebrand-modal.tsx\`](https://github.com/hexclave/stack-auth/blob/dev/apps/dashboard/src/components/hexclave-rebrand-modal.tsx)
referenced \`/logo.svg\` and \`/logo-bright.svg\` for the left-hand
"Stack Auth" mark. But the visible-rebrand flip in
[#1481](https://github.com/hexclave/stack-auth/pull/1481) replaced those
files in \`apps/dashboard/public/\` with the Hexclave benzene mark — so
post-merge, both \`<Image>\` slots resolved to the Hexclave logo.

## Fix

- Restored the **pre-rebrand Stack Auth SVGs** (lifted from
\`57ff5d3ce~1\`, the commit before the brand-flip) under dedicated
filenames so they can't get clobbered the next time \`/logo.svg\` is
updated:
- \`apps/dashboard/public/stack-auth-logo.svg\` — black mark, light
theme
- \`apps/dashboard/public/stack-auth-logo-bright.svg\` — white mark,
dark theme
- Pointed the modal's left-hand \`<Image>\` pair at the new paths and
left a comment explaining why we don't share \`/logo.svg\` (so the next
person doesn't try to consolidate it back).

The originals on \`origin/dev\` (\`/logo.svg\`, \`/logo-bright.svg\` =
Hexclave) are untouched.

## Verification

- \`pnpm --filter @stackframe/dashboard lint\` — clean.
- Diff of
[hexclave-rebrand-modal.tsx](https://github.com/hexclave/stack-auth/blob/fix-stack-logo-in-modal/apps/dashboard/src/components/hexclave-rebrand-modal.tsx)
is two \`src=\` swaps plus a comment; the dismissal logic, gates, and
storage key are untouched.

<!-- This is an auto-generated description by cubic. -->
---
## Summary by cubic
Fixes the rebrand modal to show the Stack Auth logo on the left instead
of rendering Hexclave on both sides. Restores pre-rebrand assets as
`stack-auth-logo.svg` and `stack-auth-logo-bright.svg` and updates the
modal to use them for light/dark themes.

<sup>Written for commit f4ed26266c.
Summary will update on new commits. <a
href="https://cubic.dev/pr/hexclave/stack-auth/pull/1495?utm_source=github">Review
in cubic</a></sup>

<!-- End of auto-generated description by cubic. -->



<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **Style**
* Updated the rebrand modal illustration assets to display Stack Auth
branding correctly.

<!-- review_stack_entry_start -->

[![Review Change
Stack](https://storage.googleapis.com/coderabbit_public_assets/review-stack-in-coderabbit-ui.svg)](https://app.coderabbit.ai/change-stack/hexclave/stack-auth/pull/1495?utm_source=github_walkthrough&utm_medium=github&utm_campaign=change_stack)

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<!-- end of auto-generated comment: release notes by coderabbit.ai -->

apps/dashboard/public/stack-auth-logo-bright.svg

@@ -0,0 +1,3 @@
+<svg width="131" height="156" viewBox="0 0 131 156" fill="none" xmlns="http://www.w3.org/2000/svg">
+<path d="M124.042 28.6459L69.7327 1.75616C66.9416 0.374284 63.666 0.372197 60.8735 1.75051L0.335449 31.6281V87.6369L65.3045 119.91L117.154 93.675V112.414L65.3045 138.44L0.335449 106.584V119.655C0.335449 122.359 1.87599 124.827 4.30545 126.015L61.8765 154.161C64.6911 155.538 67.9883 155.515 70.7832 154.099L130.065 124.074V79.7105C130.065 74.8003 124.934 71.5769 120.51 73.7077L79.0476 93.675V75.9771L130.065 50.1589V38.3485C130.065 34.2325 127.731 30.4724 124.042 28.6459Z" fill="white"/>
+</svg>

apps/dashboard/public/stack-auth-logo.svg

@@ -0,0 +1,3 @@
+<svg width="131" height="156" viewBox="0 0 131 156" fill="none" xmlns="http://www.w3.org/2000/svg">
+<path d="M124.447 28.6459L70.1382 1.75616C67.3472 0.374284 64.0715 0.372197 61.279 1.75051L0.740967 31.6281V87.6369L65.7101 119.91L117.56 93.675V112.414L65.7101 138.44L0.740967 106.584V119.655C0.740967 122.359 2.28151 124.827 4.71097 126.015L62.282 154.161C65.0966 155.538 68.3938 155.515 71.1888 154.099L130.47 124.074V79.7105C130.47 74.8003 125.34 71.5769 120.915 73.7077L79.4531 93.675V75.9771L130.47 50.1589V38.3485C130.47 34.2325 128.137 30.4724 124.447 28.6459Z" fill="black"/>
+</svg>

apps/dashboard/src/components/hexclave-rebrand-modal.tsx

@@ -150,9 +150,11 @@ function RebrandIllustration() {
       className="flex justify-center items-center gap-4 pb-2"
       aria-hidden="true"
     >
-      {/* Stack Auth: served light & dark variants depending on theme */}
+      {/* Stack Auth: pre-rebrand mark, preserved under a dedicated filename
+          because /logo.svg now resolves to the Hexclave benzene mark post-
+          rebrand (PR #1481). Light & dark variants served per theme. */}
       <Image
-        src="/logo.svg"
+        src="/stack-auth-logo.svg"
         alt=""
         width={48}
         height={48}
@@ -160,7 +162,7 @@ function RebrandIllustration() {
         className="h-12 w-auto opacity-50 block dark:hidden"
       />
       <Image
-        src="/logo-bright.svg"
+        src="/stack-auth-logo-bright.svg"
         alt=""
         width={48}
         height={48}