docs: the guard-a-new-vhost procedure and Audiobookshelf's second door

Infrastructure/Caddy.md now owns the order of operations for exposing a vhost
(proxy provider + application + embedded-outpost claim, then the route, then the
name and the chain audit), because the IdP row is invisible state that nobody
recreates. Audiobookshelf's Internal-only row and law become Two doors, one app;
the homepage link and index.md follow.

serverAppConfigs-docs/Infrastructure/Caddy.md

@@ -4,7 +4,7 @@ description: "Caddy is the single reverse proxy for both hosts."
 tags:
   - infrastructure
   - caddy
-timestamp: 2026-08-29
+timestamp: 2026-11-03
 ---
 
 # Caddy
@@ -90,7 +90,50 @@ pihole.franksdank.cloud {
 
 After rendering, the line reads `dankuser <hash>` (one complete hash) — `tests/deployment_flow.bats:96-99` pins the `dankuser` name and the single-hash form, and `tests/caddyfile.bats:75` pins the bare `dankuser REPLACE_WITH_HASH` template. Do not put a `$2a$14$` prefix in the template: it would render a double-prefixed, invalid hash (2026-08-22 incident — every basicauth vhost returned 401 for every password; `tests/caddyfile.bats:67-72` forbids the prefix). `tests/deployment_flow.bats` pins the render contract.
 
-Everything else authenticates, not basicauth. The guarded set — `www.` (homepage), `search.`, `grafana.`, `prometheus.`, `loki.`, `seerr.`, `marreta.`, `romm.`, `files.` — proxies **all** traffic to `anubis:8923`, which verifies the client and forwards it back to Caddy's internal listener `http://:8016`; Authentik's proxy-provider mode serves the login inline (this build exposes **no** `forward_auth` endpoint) and forwards authenticated traffic to `http://:8017`, where the request is routed straight to its app (`dankclaw/Caddyfile:14-24,283-423`). The exempt-by-construction set never enters that chain: `auth.` (the IdP itself), `ai.` and `gitea.` (own logins), `hermes.` and `hermesadmin.` (app-enforced passwords), `pihole.` (the basicauth edge above), and the media/*arr vhosts. Grafana left basicauth on 2026-09-01 and is an OAuth2 relying party against Authentik (`dankclaw/Caddyfile:122-132`). See [[Homepage]] and [[Authentik]].
+Everything else authenticates, not basicauth. The guarded set — `www.` (homepage), `search.`, `grafana.`, `prometheus.`, `loki.`, `seerr.`, `marreta.`, `romm.`, `files.`, `notebook.`, `abs.` — proxies **all** traffic to `anubis:8923`, which verifies the client and forwards it back to Caddy's internal listener `http://:8016`; Authentik's proxy-provider mode serves the login inline (this build exposes **no** `forward_auth` endpoint) and forwards authenticated traffic to `http://:8017`, where the request is routed straight to its app (`dankclaw/Caddyfile`: the header comment and the two internal listeners). The exempt-by-construction set never enters that chain: `auth.` (the IdP itself), `ai.` and `gitea.` (own logins), `hermes.` and `hermesadmin.` (app-enforced passwords), `pihole.` (the basicauth edge above), and the media/*arr vhosts. Grafana left basicauth on 2026-09-01 and is an OAuth2 relying party against Authentik (`dankclaw/Caddyfile:122-132`). See [[Homepage]] and [[Authentik]].
+
+## Guard a new vhost
+
+Order is the whole procedure: the IdP row has to exist **before** the route flips, or
+authenticated traffic reaches the outpost with no matching provider and the user gets
+authentik's error page instead of the app.
+
+1. **Provider first.** A proxy provider plus an application, claimed by the embedded
+   outpost. No blueprint owns this state — it lives only in the IdP's database, which is
+   why it is easy to forget:
+
+   ```
+   ssh dankclaw 'podman exec -i authentik-server ak shell' <<'PY'
+   from authentik.providers.proxy.models import ProxyProvider
+   from authentik.core.models import Application
+   from authentik.outposts.models import Outpost
+   NAME, EXT = "abs", "https://abs.franksdank.cloud/"
+   pp = ProxyProvider.objects.filter(name=f"{NAME}-proxy").first()
+   if pp is None:
+       pp = ProxyProvider.objects.create(name=f"{NAME}-proxy", external_host=EXT,
+                                         internal_host="http://caddy:8017")
+   if not Application.objects.filter(provider=pp).exists():
+       Application.objects.create(name=f"{NAME.title()} Guard", slug=f"{NAME}-guard",
+                                  provider=pp)
+   o = Outpost.objects.get(managed="goauthentik.io/outposts/embedded")
+   o.providers.add(pp)   # an unclaimed provider is invisible to the outpost
+   print(pp.name, pp.external_host, o.providers.count())
+   PY
+   ```
+
+   `external_host` is the exact vhost URL **with the trailing slash**: the embedded
+   outpost routes on the ORIGINAL `Host` header alone, so anything else matches zero
+   providers. Never print a provider's fields wholesale — a proxy provider carries a
+   client secret, and it lands in whatever transcript the command runs in.
+2. **Then the route.** The public site block proxies the whole request to `anubis:8923`
+   with `header_up X-Real-Ip {remote_host}`, and the post-auth `http://:8017` listener
+   gains a `@<name> host <vhost>` handler pointing at the app — copy `romm`/`files`,
+   which are the same shape including a Dankserver LAN-port upstream.
+3. **Then the name and the audit.** A `dankclaw/pihole/addn-hosts` line (the `pihole`
+   seam fails the build if a Caddyfile vhost has no record), a Porkbun A record if the
+   name must resolve off-LAN ([[LAN-DNS]]), and the subdomain added to `GUARDED` in
+   `tests/e2e/specs/14-guard.spec.ts` with an app-specific leak marker — that spec is
+   the deploy gate's proof that the guard, not the app, answers an anonymous client.
 
 ## Operations