fix: run pgBackRest directory and log file setup in stage2_nix pass

The directory and log file creation tasks were gated on nixpkg_mode
only, so they were skipped during the stage 2 Nix provision pass
(nixpkg_mode=false, stage2_nix=true). SAA is installed in stage 2 but
had no log directory or pre-created log files to write to, causing
pgbackrest enable to fail immediately.

Extend both conditions to nixpkg_mode or stage2_nix so the paths are
created in whichever pass installs the software.

Author: Crispy1975

ansible/tasks/setup-pgbackrest.yml

@@ -63,7 +63,7 @@
   loop_control:
     loop_var: backrest_dir
   when:
-    - nixpkg_mode
+    - nixpkg_mode or stage2_nix
 
 # supabase-admin-agent opens these log files with O_APPEND|O_WRONLY (no
 # O_CREATE). They must exist before SAA runs; a missing file causes the
@@ -83,7 +83,7 @@
     - /var/log/pgbackrest/wal-push.log
     - /var/log/pgbackrest/wal-fetch.log
   when:
-    - nixpkg_mode
+    - nixpkg_mode or stage2_nix
 
 - name: Symlink pgbackrest.conf
   ansible.legacy.file: