test(s034): the archive tests are SQLite's, as the archive is; docs/backup.md says what Postgres does

Run 35553598612's postgres job had no SQLite file to snapshot.

Signed-off-by: Ayla Croft <aylacroft@proton.me>

Author: HackTuah

docs/backup.md

@@ -49,6 +49,12 @@ faithful. The search index is inside the database on SQLite; on Postgres it is a
 
 `--data-dir <dir>` points either task at a directory other than the configured one.
 
+## Postgres
+
+The archive is the SQLite data directory's. A deployment on Postgres (`TRINITY_DB=postgres`) keeps its rows in
+that database and backs it up with Postgres's own tools (`pg_dump`); the export there carries the key registry
+and the directories, not the databases, and says so in the manifest's file list.
+
 ## Size
 
 On the machine this was written on (2026-09-21), 18 sessions and 8,029 messages made a 713 KB archive (3.1 MB

test/mix/trinity_import_task_test.exs

@@ -4,6 +4,9 @@ defmodule Mix.Tasks.Trinity.ImportTaskTest do
   @moduledoc "Slice 034: the import task refuses a held data directory and a non-empty one, and restores into an empty one."
   use ExUnit.Case, async: false
 
+  # The archive is the SQLite data directory\'s (docs/backup.md); the postgres job excludes :sqlite.
+  @moduletag :sqlite
+
   alias Trinity.Archive
   alias Trinity.Archive.Layout
 

test/trinity/archive/round_trip_test.exs

@@ -10,6 +10,9 @@ defmodule Trinity.Archive.RoundTripTest do
   """
   use ExUnit.Case, async: false
 
+  # The archive is the SQLite data directory\'s (docs/backup.md); the postgres job excludes :sqlite.
+  @moduletag :sqlite
+
   import Ecto.Query, only: [from: 2]
 
   alias Ecto.Adapters.SQL.Sandbox

test/trinity_web/settings_export_test.exs

@@ -4,6 +4,9 @@ defmodule TrinityWeb.SettingsExportTest do
   @moduledoc "Slice 034: the settings page links to the export; the download is a tarball whose manifest parses and names the keys choice."
   use TrinityWeb.ConnCase, async: false
 
+  # The archive is the SQLite data directory\'s (docs/backup.md); the postgres job excludes :sqlite.
+  @moduletag :sqlite
+
   import Phoenix.LiveViewTest
 
   alias Trinity.Archive.Manifest