Rebuild: the edge workers' API in its own service

The node API (leases, hour-long streams, batches of up to 256 MB JSON
parsed in-process) shared the web process with the catalog API, Newznab
and the web interface; voyager 1 had to make the same split on
2026-10-06. HTTP_ROUTES picks a process's routes (node, public, all by
default): compose service node-api (same image, port 3335 on the compose
network) serves the workers, web the rest. The workers' COORDINATOR_URL
points at node-api; deploy.sh stops edge before recreating node-api.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

start/env.ts

@@ -65,5 +65,6 @@ export default await Env.create(new URL('../', import.meta.url), {
   SPOOL_MAX_GB: Env.schema.number.optional(),
   PREFETCH_PER_RANGE: Env.schema.number.optional(),
   PROBE_CONNECTIONS: Env.schema.number.optional(),
+  HTTP_ROUTES: Env.schema.enum.optional(['all', 'node', 'public'] as const),
   PREFETCH_PER_GROUP: Env.schema.number.optional(),
 })