feat(photos): add Immich stack

Self-hosted photo backup at photos.ginnoir.com (internal/tailnet only).
Server + machine-learning + postgres (vectorchord) + redis.
Upload storage: /storage1/labdata/immich/upload (ZFS).
DB/model-cache: /config/immich/ (SSD).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

stacks/photos/stack.env

@@ -0,0 +1,15 @@
+PUID=1000
+PGID=1000
+TZ=America/Chicago
+
+# Postgres
+DB_HOSTNAME=immich-postgres
+DB_USERNAME=immich
+DB_PASSWORD=UXhnm2Gzzlm2nmJP1xWbc5L3M9Dt9TpG
+DB_DATABASE_NAME=immich
+
+# Redis
+REDIS_HOSTNAME=immich-redis
+
+# Immich
+UPLOAD_LOCATION=/usr/src/app/upload