Add shell introduction to Provisioning from the Shell chapter

Add a brief introductory section to the "Provisioning from the Shell" manual chapter before the first command block. The intro should cover what the ORE Studio shell is, how to open it, and any prerequisites (e.g. services running, environment loaded). A short paragraph and perhaps a screenshot of the shell prompt is sufficient — the goal is that a first-time reader knows where they are before commands start appearing.

Readers arriving at the chapter cold have no context for what "the shell" is in the ORE Studio sense. Without an intro they must infer it from the commands themselves, which increases confusion and reduces the chapter's value as onboarding material.

• Manual chapter: doc/manual/provisioning_from_the_shell/

• Handle long lines in manual with line wrapping