* docs: move design and API contract into docs/
* docs: add releases and versioning page
* docs: add configuration reference for server and web
* docs: add reverse proxy page
* docs: add upgrading page
* docs: add operations page and move backup and profiling docs
* docs: add getting packets in and security pages
* docs: add troubleshooting page
* docs(api): fold admin, activity, route and summary notes into the contract
* docs(deploy): add type 2 split deployment, finish the beacon rename, ignore secrets
* docs: rewrite README as the front door and share the contributor workflow
* docs: remove em dashes from prose and config comments
* docs: apply review fixes to type 2, upgrading, troubleshooting and first-run notes
* docs: fix upgrade order, restore steps, type 2 setup and contract details from review
* docs: keep the gitignore to deployment secrets and runtime state
