fix(media): verify read the library the way the servers write it

A verify run beside a running scan reported rows the scanner had just
written as MISSING, and could fail outright as "database disk image is
malformed". Both libraries live in WAL mode, and the verifier opened them
with immutable=1, which tells sqlite the file never changes: it skips the
write-ahead log, so every committed-but-uncheckpointed row is invisible.
134 MB of jellyfin.db-wal was riding past the verifier's eyes during the
2026-10-31 rescan.

Open plain mode=ro first — sqlite then reads the WAL through its -shm —
and keep immutable=1 only as the fallback for a database whose -shm
cannot be read. The bats fixture leaves a journaled move uncheckpointed
and proves the verifier still counts it landed.

tests/media_verify.bats

@@ -210,3 +210,38 @@ setup() {
     [ "${lines[3]}" = "missing from the DB: 0" ]
     [ "${lines[4]}" = "not indexed (extension ignored): 1" ]
 }
+
+# wal_case <db> — a Jellyfin database whose NEW row lives only in the
+# write-ahead log: the server has committed the rename but not checkpointed it,
+# which is the normal state of a library a scan is writing. The holder
+# connection keeps the WAL from folding into the main file, and the verifier
+# runs as a real subprocess so it faces the same files Plex and Jellyfin leave.
+wal_case() {
+    python3 - "$JFDB" "$JOURNAL" "$SHARE" "$VERIFY" <<'PY'
+import sqlite3, subprocess, sys
+db, journal, share, verify = sys.argv[1:5]
+w = sqlite3.connect(db)
+w.execute("pragma journal_mode=wal")
+w.execute("pragma wal_autocheckpoint=0")
+w.execute("insert into BaseItems (Path, Type) values ('/data/Movies/Old.mkv', 'x')")
+w.commit()
+w.execute("pragma wal_checkpoint(truncate)")
+holder = sqlite3.connect(db)  # last-connection close would checkpoint
+w.execute("update BaseItems set Path='/data/Movies/Old/Old.mkv'")
+w.commit()
+r = subprocess.run([sys.executable, verify, "--journal", journal,
+                    "--db-kind", "jellyfin", "--db", db,
+                    "--share", share, "--container", "/data"],
+                   capture_output=True, text=True)
+print(r.stdout, end="")
+sys.exit(r.returncode)
+PY
+}
+
+@test "a row the server committed but has not checkpointed is proof, not a miss" {
+    move_row "$SHARE/Movies/Old.mkv" "$SHARE/Movies/Old/Old.mkv"
+    run wal_case
+    [ "$status" -eq 0 ]
+    [ "${lines[1]}" = "landed: 1" ]
+    [ "${lines[3]}" = "missing from the DB: 0" ]
+}