chore(server): container, compose, and the Pi deployment notes

compose.yaml joins the Pi's existing network as external and reaches the
Postgres and Caddy already there by name; nothing is published to the
host. The schema applies itself on boot, so there is no migration step to
run by hand.

The Caddy snippet in the README is the part worth reading. Excluding
/api/tutor from `encode` matters more than flush_interval: compression
delays the header flush until body bytes arrive and holds already-flushed
events inside an unfinished frame, which presents as a stream that hangs
rather than as an error.

Untested against the actual Pi — written from PORT.md and verified only
as far as building the image and running it against a local Postgres.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

.dockerignore

@@ -0,0 +1,8 @@
+node_modules
+**/node_modules
+app/dist
+app/android
+export
+vendor
+.git
+*.tsbuildinfo