fix(docs): add DB_USERNAME when needed (#19578)

add DB_USERNAME when needed

docs/docs/FAQ.mdx

@@ -458,7 +458,7 @@ A result of `on` means that checksums are enabled.
 <summary>Check if checksums are enabled</summary>
 
 ```bash
-docker exec -it immich_postgres psql --dbname=postgres --username=postgres --command="show data_checksums"
+docker exec -it immich_postgres psql --dbname=postgres --username=<DB_USERNAME> --command="show data_checksums"
  data_checksums
 ----------------
  on
@@ -473,7 +473,7 @@ If checksums are enabled, you can check the status of the database with the foll
 <summary>Check for database corruption</summary>
 
 ```bash
-docker exec -it immich_postgres psql --dbname=postgres --username=postgres --command="SELECT datname, checksum_failures, checksum_last_failure FROM pg_stat_database WHERE datname IS NOT NULL"
+docker exec -it immich_postgres psql --dbname=postgres --username=<DB_USERNAME> --command="SELECT datname, checksum_failures, checksum_last_failure FROM pg_stat_database WHERE datname IS NOT NULL"
   datname  | checksum_failures | checksum_last_failure
 -----------+-------------------+-----------------------
  postgres  |                 0 |
@@ -490,7 +490,7 @@ You can also scan the Postgres database file structure for errors:
 <details>
 <summary>Scan for file structure errors</summary>
 ```bash
-docker exec -it immich_postgres pg_amcheck --username=postgres --heapallindexed --parent-check --rootdescend --progress --all --install-missing
+docker exec -it immich_postgres pg_amcheck --username=<DB_USERNAME> --heapallindexed --parent-check --rootdescend --progress --all --install-missing
 ```
 
 A normal result will end something like this and return with an exit code of `0`:

docs/docs/administration/backup-and-restore.md

@@ -57,7 +57,7 @@ Then please follow the steps in the following section for restoring the database
   <TabItem value="Linux system" label="Linux system" default>
 
 ```bash title='Backup'
-docker exec -t immich_postgres pg_dumpall --clean --if-exists --username=postgres | gzip > "/path/to/backup/dump.sql.gz"
+docker exec -t immich_postgres pg_dumpall --clean --if-exists --username=<DB_USERNAME> | gzip > "/path/to/backup/dump.sql.gz"
 ```
 
 ```bash title='Restore'
@@ -79,7 +79,7 @@ docker compose up -d            # Start remainder of Immich apps
   <TabItem value="Windows system (PowerShell)" label="Windows system (PowerShell)">
 
 ```powershell title='Backup'
-[System.IO.File]::WriteAllLines("C:\absolute\path\to\backup\dump.sql", (docker exec -t immich_postgres pg_dumpall --clean --if-exists --username=postgres))
+[System.IO.File]::WriteAllLines("C:\absolute\path\to\backup\dump.sql", (docker exec -t immich_postgres pg_dumpall --clean --if-exists --username=<DB_USERNAME>))
 ```
 
 ```powershell title='Restore'

docs/docs/guides/template-backup-script.md

@@ -52,9 +52,9 @@ REMOTE_BACKUP_PATH="/path/to/remote/backup/directory"
 ### Local
 
 # Backup Immich database
-docker exec -t immich_postgres pg_dumpall --clean --if-exists --username=postgres > "$UPLOAD_LOCATION"/database-backup/immich-database.sql
+docker exec -t immich_postgres pg_dumpall --clean --if-exists --username=<DB_USERNAME> > "$UPLOAD_LOCATION"/database-backup/immich-database.sql
 # For deduplicating backup programs such as Borg or Restic, compressing the content can increase backup size by making it harder to deduplicate. If you are using a different program or still prefer to compress, you can use the following command instead:
-# docker exec -t immich_postgres pg_dumpall --clean --if-exists --username=postgres | /usr/bin/gzip --rsyncable > "$UPLOAD_LOCATION"/database-backup/immich-database.sql.gz
+# docker exec -t immich_postgres pg_dumpall --clean --if-exists --username=<DB_USERNAME> | /usr/bin/gzip --rsyncable > "$UPLOAD_LOCATION"/database-backup/immich-database.sql.gz
 
 ### Append to local Borg repository
 borg create "$BACKUP_PATH/immich-borg::{now}" "$UPLOAD_LOCATION" --exclude "$UPLOAD_LOCATION"/thumbs/ --exclude "$UPLOAD_LOCATION"/encoded-video/