feat(portal): MCP teaser + README portal hero & tools section

[KB-x]

What's New

Promotion-focused polish across the portal and repo README:

1. Portal: a "Coming soon: JVD MCP Server" teaser above the footer, previewing the Deploy stage, with a Notify me — Watch on GitHub button.
2. README hero: a clickable JVD Portal door graphic + CTA + DISCOVER · LEARN · DESIGN · BUILD at the top of the repo.
3. README portal section: revamped the stale "Snip Libraries and BYOAI" section into a current The JVD Portal overview (Config Explorer, BYOAI Config + Design, Service Generator, MCP coming soon), with a theme-adaptive BYOAI robot.

Why

Make the portal the front door of the repo and build anticipation ahead of the public announcement, while removing outdated/duplicated copy. (Repo topics + description were also refreshed for discoverability — applied as repo settings, not part of this PR.)

Details

• portal/src/components/JvdPortal.tsx — new #mcp teaser section (PlugZap icon, "Coming soon" pill, tracked mcp-notify button). No nav / existing-tool changes.
• README.md — new hero (door → portal); removed the redundant portal blockquote; rewrote the bottom section to reflect current portal tools.
• portal/src/assets/jvd-portal.png — README hero door graphic.
• portal/src/assets/jvd-bot.png (white) + jvd-bot-black.png (inverted) — theme-adaptive robot via a <picture> element (white in dark mode, black in light mode).

Testing

• bun run build — clean, no type errors.
• README images referenced by repo-relative paths so they render on GitHub; door + robot confirmed in dark mode.

Notes

• Social preview image (door, 1280×640) is a separate repo-Settings upload.
• Notify button can later point at a dedicated tracking issue if we want an interest signal.