fix(assets): replace hero brand mark with website coral circuit mark (affaan-m#2232)

* fix(assets): replace hero brand mark with website coral circuit mark

The top-left mark in the hero banner was the assets/ecc-icon.svg double-E
lettermark, not the actual brand logo. Swap in the coral vector circuit
mark from the ECC-website header (src/styles/brandMarks.ts), keeping the
~70px footprint, the soft coral glow, and every other element identical.
PNG re-rendered at 2400x1350 via sharp with palette compression.

* docs: sync skill count to 262 across catalog surfaces

catalog:check was failing on main after config-gc (affaan-m#2216) landed without
a count bump. Ran npm run catalog:sync.

Author: affaan-m