Kinsta Sync 1.1.7

1.1.7 — fix clean-install crash + sync hardening

Clean-install crash (release blocker): the renderer bundled a bare
require("react-router-dom") via a webpack external, but react-router-dom is
only a devDependency, so it is absent from the released .tgz. Local require()s
the renderer from the add-on dir (outside its asar) -> MODULE_NOT_FOUND ->
the add-on's export default never runs -> no hooks register (no UI) and Local's
shell crashes with "Cannot read properties of undefined (reading 'toString')".
Now consume Route via context.ReactRouter and drop react-router-dom from
webpack externals; bundle.packaging.test.ts asserts every non-relative require
in the built renderer is resolvable on a clean install.

Sync hardening (informed by reading WP Engine's Magic Sync internals):

• SSH keepalive (ServerAliveInterval=60 / ServerAliveCountMax=120) on all ssh
  and rsync calls so long steps are not dropped by an idle NAT/firewall
• --skip-plugins --skip-themes on both remote wp db export calls (protects
  the pull export and the pre-push rollback backup from a broken plugin)
• downgrade utf8mb4_0900_* collations to utf8mb4_unicode_520_ci before push
  (Local ships MySQL 8; Kinsta runs MariaDB, which rejects 0900 collations)
• push-side table_prefix reconcile (push is now symmetric with pull; non-fatal)
• exclude host-specific object-cache.php / advanced-cache.php drop-ins

Full Changelog: v1.1.6...v1.1.7