ombi: reach plex through the mesh, in the same step as the Servarr apps

ombi reached plex at its public name, typed into its settings screen, so it
depended on plex's public route and on nobody moving plex. ombi now requires
plex-api, and the run-once step that writes its Servarr connections writes
its Plex one too - renamed from `servarr` to `connections`, since it is no
longer only that.

ombi keeps several Plex servers. The entry this provision names is found by
the server's own machineIdentifier (plex answers it at /identity, and ombi
stored it when the server was loaded), and only its host, port, TLS, base
path and token are written, only when they differ. Another server's entry,
the selected libraries, whether Plex is enabled and every other choice are
left alone. An ombi with no entry for the server gets one.

The token is tried against plex first. Until the operator accepts the
server's X-Plex-Token for this pair the mesh delivers a value it minted,
which plex refuses (401, or 400 on a network it trusts); refused, nothing is
written and the step fails naming the secret accept, so a working token in
ombi is never replaced by a dead one.

Tests import the compiled step, as keycloak's do: the step imports its
sibling with the .js specifier the build needs, which type stripping does
not resolve. `npm test` builds first.

modules/ombi/Dockerfile

@@ -13,7 +13,7 @@ ARG RUNTIME_BASE
 FROM ${BUILD_BASE} AS build
 WORKDIR /app/modules/ombi
 COPY . .
-RUN node /app/node_modules/typescript/bin/tsc client.ts index.ts tools/index.ts servarr/settings.ts servarr/index.ts \
+RUN node /app/node_modules/typescript/bin/tsc client.ts index.ts tools/index.ts servarr/settings.ts plex/settings.ts connections/index.ts \
       --module NodeNext --moduleResolution NodeNext --target ES2022 --outDir dist
 
 FROM ${RUNTIME_BASE}
@@ -22,6 +22,6 @@ COPY --from=build /app/modules/ombi/dist /app/modules/ombi/dist
 # provider's provisioner runs its reconcile loop in the same process, with the broker connected —
 # the convention novox/hq issues 060/061 settled.
 ENV MESH_TOOL_MODULES=/app/modules/ombi/dist/index.js,/app/modules/ombi/dist/tools/index.js
-# NOT dist/servarr/index.js: that is a step the host runs to completion, named by the `servarr`
+# NOT dist/connections/index.js: that is a step the host runs to completion, named by the `connections`
 # container's args as `mesh-tools run …` (novox/hq ADR 0052). Listed here it would run inside the
 # serving sidecar too, and exit it.