chore: release 1.2.3

[WhiteMuush]

Version bump ahead of the v1.2.3 tag, so the tagged commit already carries the version it releases.

Covers the two changes merged since v1.2.2:

• fix(deps): clear the high npm audit findings on mysql2 and browserslist #181 cleared three high-severity npm audit findings (mysql2 auth plugin downgrade leaking plaintext credentials, plus two browserslist advisories) through package.json overrides.
• build(deps): fold in the three open Dependabot groups #183 folded in the three open Dependabot groups by hand, including the Better Auth 1.7 upgrade and the Account.issuer schema migration it requires.

Deploying v1.2.3 needs prisma migrate deploy to run before the new build serves traffic.