Stop per-heartbeat re-auth log spam; stop logging bearer tokens

Two issues found while investigating repeated "Re-authentication required for
Test player (rpi-test1): token_reset" entries appearing every ~20s.

1) Log spam. The heartbeat handler logged an INFO row every time it asked a
   player to re-authenticate. A player heartbeats every ~15s and the request
   repeats until the player complies, so a pending request wrote a server_log
   row every few seconds (~230 rows in ~1.3h here) and buried the dashboard.

   The per-heartbeat log line is removed. The request is now recorded once, at
   the moment it is raised: the admin action already logs when the button is
   pressed, and the automatic interval now logs at its transition. The
   outstanding request stays visible in Admin -> Maintenance as
   "awaiting re-auth".

2) Credential leak. verify_player_auth logged the rejected value in full
   ("Invalid auth code attempt: <token>"). server_log is readable in the UI and
   the database, so this wrote a live bearer token to a readable store. It now
   logs a 6-character prefix plus the client IP, which is enough to correlate
   failures without exposing the credential.

app/blueprints/api.py

@@ -78,7 +78,13 @@ def verify_player_auth(f):
         player = Player.query.filter_by(auth_code=auth_code).first()
         
         if not player:
-            log_action('warning', f'Invalid auth code attempt: {auth_code}')
+            # Never log the whole token: server_log is readable in the UI (and
+            # the DB), so writing a bearer value there would leak a credential.
+            # A short prefix is enough to correlate repeated failures.
+            token_hint = f'{auth_code[:6]}…' if auth_code else '(empty)'
+            log_action('warning',
+                       f'Invalid auth code attempt (token {token_hint}, '
+                       f'client {request.remote_addr})')
             return jsonify({'error': 'Invalid authentication code'}), 403
         
         # Store player in request context
@@ -143,9 +149,19 @@ def player_needs_reauth(player: Player):
         return False, None
 
     if datetime.utcnow() - issued >= timedelta(days=interval_days):
-        # Flag the player; the replacement token is issued when it re-auths.
+        # Raise the request and record it ONCE, at the transition.
+        #
+        # This deliberately does not log per request: a player heartbeats every
+        # ~15s, so logging each time it is asked would add a server_log row
+        # every few seconds and drown the dashboard. The pending request stays
+        # visible in Admin -> Maintenance as "awaiting re-auth", which is the
+        # place to look, and the admin-triggered path is logged where the admin
+        # presses the button.
         player.request_reauth()
         db.session.commit()
+        log_action('info',
+                   f'Auth token interval elapsed for {player.name} '
+                   f'({player.hostname}) — re-authentication requested')
         return True, 'token_expired'
 
     return False, None
@@ -570,12 +586,14 @@ def receive_player_feedback():
         #
         # This runs before any feedback is recorded: the heartbeat is not a
         # meaningful status update while the client is being asked to
-        # re-authenticate.
+        # re-authenticate. Note there is intentionally NO log line here — the
+        # request repeats on every heartbeat (~15s) until the player complies,
+        # which would flood server_log. The outstanding request is visible in
+        # Admin -> Maintenance ("awaiting re-auth") and is logged once where it
+        # is raised (admin action, or the interval transition above).
         # ------------------------------------------------------------------
         needs_reauth, reauth_reason = player_needs_reauth(player)
         if needs_reauth:
-            log_action('info', f'Re-authentication required for {player.name} '
-                               f'({player.hostname}): {reauth_reason}')
             return jsonify({
                 'success': False,
                 'auth_required': True,