Documentation cleanup for public release (#123)

Prepares the docs for the public release announcement: removes obsolete/dead
material, fixes drift between the API reference and the actual routes, and
standardizes on the default GitHub Pages URL.

- Remove Vagrant entirely: delete Vagrantfile, docs/dev_setup.md, and stale
  vagrant references in .gitignore/.dockerignore; rewrite openresty/README.md
  to describe the actual (currently unused) directory and point to
  ops/nginx_conf/ for the real OpenResty config.
- Delete docs/Update 4.11.md (personal scratch changelog) and drop both its
  and dev_setup.md's references from docs/README.md's Legacy Documentation
  section.
- Remove checkmark emoji from docs/contributing.md's PR Requirements list.
- Bring the auth model docs up to date with the code: document
  GET /api/auth/oidc/start + /callback, the /api/permission and /api/group
  RBAC routers, the /api/dns/dynamic/* sub-API, and /api/api-token (self
  -service PATs) in both nodejs/api.md and docs/api.md; add the missing
  "Clear Host Cache" section; drop the invite-token/SSH-key endpoints that no
  longer exist in nodejs/routes/user.js; note admin-only routes. Mention
  OIDC/LDAP/RBAC as core features in README.md.
- Keep nodejs/api.md and docs/api.md fully in sync (same body, differing only
  in Jekyll front matter / relative links) instead of letting them drift.
- Fix Node.js version references (20.x -> 22.x) in README.md and
  docs/installation.md to match ops/install.sh and the Dockerfile.
- Note that the manual nginx-conf/systemd install steps in README.md and
  docs/installation.md won't auto-track repo changes the way install.sh's
  symlink approach does, and recommend install.sh.
- Update the stale test/unit file lists in docs/contributing.md and
  nodejs/test/README.md to match the actual directory contents.
- Add npm run test:integration to README.md's Running Tests section.
- Add nodejs/conf/, nodejs/controller/, and nodejs/migrations/ to the project
  structure diagrams in README.md, docs/architecture.md, and
  docs/contributing.md.
- Standardize "CloudFlare" -> "Cloudflare" everywhere to match the actual API
  value in nodejs/models/dns_provider.js.
- Add the missing app_auth__adminGroups row to DEPLOYMENT.md's app_* table.
- Delete docs/CNAME (custom domain) so GitHub Pages serves from the default
  https://theta42.github.io/proxy/, matching docs/README.md.

Co-authored-by: Claude Sonnet 5 <noreply@anthropic.com>

openresty/README.md

@@ -1,9 +1,10 @@
-The folder will hold a link to the openresty conf file. Nothing in here will be
-tracked, and edits are only valid on you local VM. The contents of this folder
-is also reset during each provision run. Be mind full of that when making
-changes here.
+This directory is currently unused.
 
-To apply any changes made in this folder, run the following command from outside
-the VM:
+The real OpenResty/nginx configuration for this project lives in
+[`ops/nginx_conf/`](../ops/nginx_conf/) (`nginx.conf`, `autossl.conf`,
+`proxy.conf`, `targetinfo.lua`, `hostfeatures.lua`). `ops/install.sh` symlinks
+those files into place on a bare-metal host, and the Docker image copies them
+in at build time — see [`DEPLOYMENT.md`](../DEPLOYMENT.md) for details.
 
-`vagrant ssh -c "sudo service openresty restart"`
+If you're looking for how to change the nginx/Lua configuration, edit the
+files under `ops/nginx_conf/` instead of this directory.