knot: use aesthetic.computer/core repo URL (no .git suffix)
Tangled's self-hosted knot (knot.aesthetic.computer) stores repos on
disk at /home/git/repositories/<DID>/<repo> with no .git suffix. The
handle form resolves aesthetic.computer → did:plc:k3k3wknzkc... at
request time. Using `aesthetic.computer/core.git` makes the knot look
for a non-existent `core.git/` path on disk and fail with misleading
"access denied" (SSH) or 404 (HTTP).
Update the four infra references that still used the old
aesthetic-computer.git name to the new aesthetic.computer/core form.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>