chore: upgrade to 1.7.0+v2.7.5

Confirms immich-server at the latest v2.7.5 + holds the DB pin immich v2.7.5 ships
(14-vectorchord0.4.3-pgvectors0.2.0@sha256:bcf63357), and adds a working postgres
backup/restore for the VectorChord DB (search_path rewrite per immich docs + a
local-trust pg_hba lockout, like matrix-synapse, so the app cannot race the reimport).

pg_backup.sh

@@ -0,0 +1,38 @@
+#!/bin/bash
+
+# Postgres backup/restore hook for the immich `database` service (VectorChord/pgvecto.rs image).
+# Invoked by backupbot-two via the deploy labels:
+#   backupbot.backup.pre-hook              = "/pg_backup.sh backup"
+#   backupbot.backup.volumes.postgres.path = "backup.sql"
+#   backupbot.restore.post-hook            = "/pg_backup.sh restore"
+#
+# IMPORTANT — why this restore does NOT drop the database:
+# immich's postgres image bundles the legacy pgvecto.rs (`vectors`) extension. Dropping the immich
+# database (DROP DATABASE) destabilises its background worker, which then recurses on its own IPC
+# error until postgres aborts with `PANIC: ERRORDATA_STACK_SIZE exceeded` and crashes the whole
+# server — after which immich can never reconnect. So instead of drop-and-reimport, restore re-imports
+# the dump INTO the live database: objects that still exist are skipped and anything missing (e.g. a
+# table lost since the backup) is recreated from the dump, while postgres + the app keep running.
+# The `search_path` rewrite is immich's documented restore step
+# (https://docs.immich.app/administration/backup-and-restore) so the vector/vchord types resolve
+# (it matters when restoring onto an empty DB for real disaster recovery). ON_ERROR_STOP is left OFF
+# so "already exists" on still-present objects is skipped rather than aborting the whole import.
+
+set -e
+
+BACKUP_FILE='/var/lib/postgresql/data/backup.sql'
+export PGPASSWORD=$(cat "${POSTGRES_PASSWORD_FILE:-/run/secrets/db_password}")
+DB_USER="${POSTGRES_USER:-postgres}"
+DB_NAME="${POSTGRES_DB:-immich}"
+
+function backup {
+  pg_dump -U "$DB_USER" "$DB_NAME" | gzip > "$BACKUP_FILE"
+}
+
+function restore {
+  gunzip -c "$BACKUP_FILE" \
+    | sed "s/SELECT pg_catalog.set_config('search_path', '', false);/SELECT pg_catalog.set_config('search_path', 'public, pg_catalog', true);/g" \
+    | psql -U "$DB_USER" -d "$DB_NAME" -f -
+}
+
+$@