Fix invalid Dispatch logo image warning

[joryirving]

Bug

Dispatch logs this runtime warning:

```
⨯ The requested resource isn't a valid image for /images/logo.png received null
```

Likely root cause

`src/app/layout.tsx` references `/images/logo.png` through `next/image`, but the runtime image either does not include a valid `public/images/logo.png` asset or the file is invalid.

Expected behavior

The app shell should not log image errors for the Dispatch logo.

Suggested fix

Pick one:

• Add a small valid `public/images/logo.png` asset.
• Replace the `next/image` logo usage with a simple text/icon fallback.
• Do not introduce remote image config.

Tests / validation

• Check existing layout tests and add coverage if useful.
• `npm ci`
• `npx prisma generate`
• `npm run lint`
• `npm run typecheck`
• `npm run test`
• `npm run build`
• `docker build -t dispatch:test .`

[joryirving]

I have opened #239 to fix this — replacing next/image with a plain <img> tag for the logo since it is a static asset from public/. This eliminates the runtime warning without needing to introduce remote image config or replace the asset.