docs(blog): PocketJS on the BlackBerry Classic

[HalfSweet]

Stacked on feat/blackberry-classic — the BlackBerry Classic host code. Base is the feature branch, so this reviews as just the blog diff on top of the hosts; retarget to main after the host branch lands.

Adds the engineering blog post for the BlackBerry Classic port — the same PocketJS guest run through two native stacks (QNX-native BAR on a rooted device + Android Runtime API-18 APK on a stock one), diverging only below the QuickJS bridge.

Covers:

• QNX's microkernel + Screen compositor / window-group model, the BPS event loop, Cascades
• the security model and the dead signing servers a community root project (bb10.root.sx) reopened
• BlackBerry's two-protocol PC link — HTTPS+CGI+XML to manage/update, SMB/CIFS to mount files
• MSC (SD-card-only) vs the MTP that was never chosen
• the optical trackpad mapped as just another relative axis

Contents:

• site/content/blog/blackberry-classic.md — new post (author HalfSweet, 2026-08-19), 5 inline SVG diagrams, 9 code snippets
• site/nav.ts — registered in BLOG_POSTS
• site/assets/blog/blackberry-classic-hero-720.png — hero photo (Hero demo on real hardware)

Draft — verified the post renders through the site's marked + shiki pipeline (SVGs pass through, tsx/c/text blocks highlight, tables render). The commit is unsigned (--no-gpg-sign, no TTY in the automation shell).