feat(shell): give every Dashboard page a real URL

The Dashboard had one address. The API served the page only at `/`, both
reference proxies forwarded only `/`, and the open module lived in React
state, so a refresh went back to the first module, nothing could be
bookmarked, and Back left the Dashboard (DESIGN.md §2.7).

ADR 0057 makes the address bar the source of truth:

- `/` is a host-owned Overview, now the landing page; `/modules/<id>`
  mounts that module. An id the server's navigation does not list shows
  "This page isn't available" and loads nothing; any other Dashboard
  address is a host-owned "Page not found".
- `/modules`, `/settings`, and `/account` are reserved whole, from one
  list (`@ekklesia/shell/dashboard-routes`) that the shell's router and
  the API's page routes both read. The API serves the same frozen page,
  ETag, and security headers anywhere inside them; look-alikes and other
  methods stay the sanitized 404.
- A small host-owned history replaces the selected-module state, built in
  the entry point so it stays the only file touching `window`. Navigation
  items are real links; modified clicks are left to the browser. Focus
  moves to the page after an in-place change, and the tab is named after
  the page.
- Sign-in still happens in place with no return value (ADR 0034), so a
  deep link opens its own page after sign-in.
- Both reference Caddyfiles forward the new paths; the deploy smoke now
  reloads a module's address through the real proxy and requires it to
  mount again.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

deploy/README.md

@@ -241,6 +241,12 @@ Module storage is installation state: back it up with the database and the bucke
    `docker compose run --rm migrate node core/dist/cli/apply-migrations.js`.
 5. **Restart on the new image:** `docker compose -f compose.yaml -f compose.proxy.yaml up -d --wait`.
 
+**Upgrading to a release with Dashboard page addresses (ADR 0057):** compare your `Caddyfile` with
+the new `Caddyfile.example` (or `Caddyfile.split.example`). The Dashboard's matcher gains `/modules`,
+`/settings`, `/account` and everything below each; without them the Dashboard still opens at `/`,
+but refreshing or bookmarking any other Dashboard page is the proxy's `404`. Reload the proxy after
+editing it.
+
 ### Rolling back
 
 Set `EKKLESIA_IMAGE` back to the previous tag and run `up -d --wait` again. That is enough only when
@@ -263,7 +269,7 @@ The same image serves both; only configuration differs.
 
 | Hostname | Serves | Refuses (`404`) |
 | --- | --- | --- |
-| Dashboard (`EKKLESIA_DASHBOARD_HOSTNAME`) | `/` and `/assets/ekklesia-dashboard/*` | everything else, including `/api/*` |
+| Dashboard (`EKKLESIA_DASHBOARD_HOSTNAME`) | `/`, the Dashboard's pages (`/modules`, `/settings`, `/account`, each with everything below it), and `/assets/ekklesia-dashboard/*` | everything else, including `/api/*` |
 | API (`EKKLESIA_HOSTNAME`) | `/api/*`, `/display/*`, `/assets/ekklesia-display/*` | everything else, including `/` |
 | Storage (`EKKLESIA_STORAGE_HOSTNAME`) | signed object URLs, unchanged | |
 
@@ -339,7 +345,10 @@ networks:
 
 Then make your proxy do what `Caddyfile.example` does:
 
-- forward `/`, `/api/*`, `/display/*`, and `/assets/*` on the Ekklesia hostname to `api:3000`;
+- forward `/`, `/api/*`, `/display/*`, and `/assets/*` on the Ekklesia hostname to `api:3000`,
+  and the Dashboard's pages: `/modules`, `/settings`, and `/account`, each bare and with everything
+  below it (ADR 0057) — without them, refreshing any Dashboard page other than `/` is your proxy's
+  `404`;
 - **overwrite** `X-Forwarded-For` with the one client address it resolved, and strip
   `CF-Connecting-IP`, `X-Real-IP`, `Forwarded`, and `True-Client-IP`;
 - stream responses on `/api/v1/module-realtime/*` without buffering (Server-Sent Events);
@@ -405,7 +414,7 @@ deployment:
 
 | # | Item | Where it is met |
 | --- | --- | --- |
-| 1 | The proxy forwards the Dashboard and `/api` on the intended origin | `Caddyfile.example` routes `/`, `/api/*`, `/display/*`, `/assets/*` on one hostname to `api`; the API serves the Dashboard itself. In the split topology, `Caddyfile.split.example` gives each hostname exactly its own paths and the exact trusted-origin CORS of ADR 0045 covers the rest. |
+| 1 | The proxy forwards the Dashboard and `/api` on the intended origin | `Caddyfile.example` routes `/`, the Dashboard's pages (`/modules`, `/settings`, `/account` and below), `/api/*`, `/display/*`, `/assets/*` on one hostname to `api`; the API serves the Dashboard itself. In the split topology, `Caddyfile.split.example` gives each hostname exactly its own paths and the exact trusted-origin CORS of ADR 0045 covers the rest. |
 | 2 | The origin port is unreachable from the Internet | The base publishes no port; only `proxy` publishes 80 and 443. |
 | 3 | The origin port is unreachable from untrusted networks | `api` is reachable only on Docker networks; `EKKLESIA_PUBLISH_ADDRESS` limits the proxy to one interface. Firewall the host itself. |
 | 4 | The proxy overwrites the trusted client-IP header | `header_up X-Forwarded-For {client_ip}` in `Caddyfile.example`. |