Add custom Open Graph (social preview) image

[Pivii]

Goal

Upload a custom Open Graph image (1280×640) so that links to this repo on Twitter / LinkedIn / Reddit / Slack render with branded artwork instead of the default GitHub avatar.

Why

Currently any share of github.com/getdictus/dictus-android shows the default GitHub gray preview. A branded OG image significantly improves click-through on social shares.

Acceptance criteria

• Design a 1280×640 image using assets from dictus-brand
• Should include: Dictus logo + wordmark, tagline "Offline voice dictation for Android", Android platform badge
• Follow the dark glassmorphism brand direction (Ink Deep #0A1628 background, Accent Blue #3D7EFF highlights)
• Upload via repo Settings → General → Social preview → Upload an image
• Verify with https://www.opengraph.xyz/url/https%3A%2F%2Fgithub.com%2Fgetdictus%2Fdictus-android

Tools

• Figma, Sketch, or directly edit the brand kit HTML in dictus-brand
• For consistency, do iOS / Android / Desktop together (one template, swap platform name + badge)