revert(infographics): restore previous ecosystem hero; archive 2026-06-14 regen as JPG

The Nano Banana 4K triptych regen didn't land aesthetically. Restore the prior
docs/diagrams/linkedInEcosystem.png (referenced by README) and keep the 58 MB
regen compressed as docs/diagrams/regen-2026-06-14/linkedInEcosystem.jpg.
Also drops the repo back under GitHub's 50 MB file warning.

Bumps agentbox submodule to 3569582 (same revert applied to its hero).

Co-Authored-By: jjohare <github@thedreamlab.uk>

Author: jjohare