…27547)

ref https://linear.app/ghost/issue/PLA-33/

Follow-up to #27544 and #27545. The auto-start flow shipped in #27545 used a `runOn: "folderOpen"` task in `.vscode/tasks.json`, which fires on **host** VS Code too — before the user clicks "Reopen in Container". On a fresh clone the host has no `node_modules`, so the task crashes with `sh: nodemon: command not found` + `Command "nx" not found`, greeting first-time contributors with a wall of red errors.

This PR moves auto-start into the **devcontainer lifecycle** so it only fires inside the container, and also fixes a second fresh-clone failure mode discovered while testing: Ghost's backend crashes importing `@tryghost/parse-email-address` because its `build/` output doesn't exist yet.

The `/mail/u/<email>/` path only resolves when that exact address is
already signed in at the `<X>` account slot, so Workspace accounts and
signed-out users hit a 404 before the `#search` fragment could run.
Switched to `/mail/u/0/?authuser=<email>`, which uses Gmail's own
account resolver and falls through to the sign-in flow instead of
erroring.