Filter turnadmin -l log noise before parsing usernames

Live run surfaced it: this coturn build writes its own startup log lines
("INFO SQLite connection was closed.", "INFO log file opened: ...") to
turnadmin -l's STDOUT, not stderr — 2>/dev/null never caught them, so
they got parsed as if they were usernames, producing nonsensical
"Database has user '2026-...INFO SQLite connection was closed.'" warnings
on a real run. A genuine "user[realm]" line never contains a space; every
log line does, so filtering on that is a simple, build-independent fix.

Also diagnosed the actual underlying failure this surfaced: coturn's live
user database was genuinely empty (both 'asterisk' and 'mattermost' had
cached credential files but neither was registered in the DB) — exactly
the container/volume-recreated-without-db drift this script's consumer
cross-check exists to catch, confirmed against a real run.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01H4k6J1qXXyYxhGEgnJaMvn

tools/coturn-test-check.sh

@@ -76,7 +76,14 @@ ok "Relay port range: ${COTURN_MIN_PORT}-${COTURN_MAX_PORT}"
 # ── Registered consumers ──────────────────────────────────────────────────────
 section "Registered consumers"
 
-DB_USERS="$(docker exec coturn turnadmin -l -b /var/lib/coturn/turndb 2>/dev/null | sed -E 's/\[.*//' | awk 'NF' | sort -u)"
+# turnadmin -l writes its own startup log lines ("INFO SQLite connection
+# was closed.", "INFO log file opened: ...") to STDOUT on at least some
+# coturn builds, not stderr — confirmed live, `2>/dev/null` alone let them
+# through and got misparsed as usernames. A real "user[realm]" line never
+# contains a space; every log line here does, so filtering those out is a
+# safe, simple way to keep only genuine entries regardless of which coturn
+# build's log-noise happens to leak onto stdout.
+DB_USERS="$(docker exec coturn turnadmin -l -b /var/lib/coturn/turndb 2>/dev/null | grep -v ' ' | sed -E 's/\[.*//' | awk 'NF' | sort -u)"
 if [ -z "$DB_USERS" ]; then
     warn "No users found in coturn's own database — nothing has actually registered yet, or turnadmin -l's output format changed. Raw:"
     docker exec coturn turnadmin -l -b /var/lib/coturn/turndb 2>&1 | sed 's/^/         /'