fix(cli): give journald each log line's priority

journald stored every daemon line at info, so journalctl -p warning,
which TROUBLESHOOTING.md asks reporters for, was always empty (B258).
When fd 1 is the journal stream, prefix lines with <N> and drop colours.

docs/BUGS.md

@@ -83,7 +83,6 @@ original wording.
 | [B261](#b261--a-folder-that-has-never-synced-reads-up-to-date) | A folder that has never synced reads "up to date" | Not fixed |
 | [B260](#b260--the-poll-pushes-a-new-folders-first-sync-behind-every-other-folder) | The poll pushes a new folder's first sync behind every other folder | Not fixed |
 | [B259](#b259--the-sync-engine-can-die-or-hang-and-nothing-shows-it-until-a-restart) | The sync engine can die or hang, and nothing shows it until a restart | Not fixed; the trigger in #53 is not known |
-| [B258](#b258--journalctl--p-warning-shows-nothing-whatever-the-daemon-logged) | `journalctl -p warning` shows nothing, whatever the daemon logged | Not fixed |
 | [B134](#b134--a-file-deleted-online-while-the-drain-checks-its-write-is-kept-as-a-conflict-copy) | A file deleted online while the drain checks its write is kept as a conflict copy | Only with `local_first` off |
 | [B91](#b91--the-daemon-hung-overnight-and-nothing-could-say-what-it-was-waiting-on) | The daemon hung overnight, and nothing could say what it was waiting on | The cause is not diagnosed; the daemon now reports where it is stuck and is restarted |
 | [B67](#b67--fresh-state-restore-can-silently-select-a-new-device-high-22) | Fresh-state restore can silently select a new device (HIGH-22) | An ambiguous device after a loss of local state is not asked about |
@@ -116,6 +115,7 @@ a live account since.
 
 | Entry | Title |
 |---|---|
+| [B258](#b258--journalctl--p-warning-shows-nothing-whatever-the-daemon-logged) | `journalctl -p warning` shows nothing, whatever the daemon logged |
 | [B256](#b256--pdfs-copy-right-after-a-save-copies-the-old-version) | `pdfs copy` right after a save copies the old version |
 | [B255](#b255--a-synced-folder-whose-files-are-all-gone-here-is-stuck-for-good) | A synced folder whose files are all gone here is stuck for good |
 | [B254](#b254--an-edit-in-the-same-second-as-a-new-upload-never-arrives) | An edit in the same second as a new upload never arrives |
@@ -712,7 +712,7 @@ the pass age and the queue in `Diagnostics`.
 
 ### B258 — `journalctl -p warning` shows nothing, whatever the daemon logged
 
-**Status:** Open
+**Status:** Fixed, not verified live
 **Found:** 2026-10-31, issue #53: the reporter ran `journalctl --user -u proton-drive.service -b
 -p warning`, as `docs/TROUBLESHOOTING.md` tells them to, and got `-- No entries --`.
 **Where:** `main` in `crates/pdfs-cli/src/main.rs`; `packaging/proton-drive.service`
@@ -725,8 +725,15 @@ stores every line of a service's output at the unit's default priority, info, un
 starts with a `<N>` prefix. So every `WARN` and `ERROR` line is stored as info, and the
 troubleshooting guide's filter hides all of them.
 
-**Fix.** Not done. When `JOURNAL_STREAM` says the output goes to journald, start each line with
-the `<N>` prefix for its level.
+**Fix.** When standard output is the journal stream (`JOURNAL_STREAM` names the same
+device and inode as fd 1), each line starts with the `<N>` prefix for its level, and ANSI colours
+are off. A terminal that merely inherited `JOURNAL_STREAM` keeps the plain format
+(`crates/pdfs-cli/src/journal.rs`).
+
+**Test:** `each_line_opens_with_the_priority_of_its_level` and
+`journal_stream_must_name_the_same_file` in `pdfs-cli`. On 2026-10-31, `pdfs diagnose` run with
+`RUST_LOG=debug` under `systemd-run --user -p StandardOutput=journal` stored its debug lines at
+`PRIORITY=7` and its report at 6.
 
 ---