feat: relay auto-control by frequency / band (PstRotator-style)

Automatically switches the Station Control relay boards from the rig's
current frequency / band. Each relay carries one rule: off (manual), a
frequency window (ON inside [lo,hi] kHz, OFF outside), or a set of bands
(ON on those bands, OFF elsewhere). Evaluated on every CAT frequency/band
change; a relay is only switched when its desired state actually changed,
so tuning within a range doesn't hammer the board.

A cached atomic flag keeps the CAT hot path a no-op when the feature is off
(important during FT8 slice churn). Saving re-applies from the live
frequency so a changed rule takes effect immediately.

New Settings → Hardware → Relay auto-control section: master enable plus a
per-relay mode (Off / Frequency / Band) with kHz range inputs or band
chips, per configured relay board. i18n EN + FR. Azimuth/Time modes (the
other two PstRotator tabs) are left for later.

frontend/src/lib/i18n.tsx

@@ -125,6 +125,13 @@ const en: Dict = {
   'station.title': 'Station Control', 'station.rotator': 'Rotator', 'station.rotatorNoRead': 'No heading read', 'station.pattern': 'Pattern', 'station.bi': 'Bi', 'station.retract': 'Retract elements', 'station.moving': 'MOVING', 'station.elements': 'Elements (mm)', 'station.read': 'Read', 'station.readLengths': 'Read current element lengths from the controller', 'station.noLengths': 'Lengths unknown — click Read to fetch them from the controller.', 'station.element': 'Element', 'station.reflector': 'Reflector', 'station.driven': 'Driven', 'station.director': 'Dir', 'station.set': 'Set', 'station.elementsHint': 'Each press lengthens/shortens the element by 2 mm (like the physical console). Verify which element responds on your antenna.', 'station.setExactLen': 'Click to type the exact current length (fixes the baseline if the auto-read is off).', 'station.atMax': 'Controller refused — the element is likely at its maximum length for this band, so it can\'t extend further.', 'station.go': 'Go', 'station.stop': 'Stop', 'station.dragHint': 'Drag a widget by its card to reorder. Pick a column count to lay them out in a grid.', 'station.colsAuto': 'Auto', 'station.addDevice': 'Add device', 'station.editDevice': 'Edit device', 'station.empty': 'No relay boards yet. Add a WebSwitch 1216H or a KMTronic 8-relay board to control your station power and accessories.', 'station.online': 'Online', 'station.offline': 'Offline', 'station.edit': 'Edit', 'station.delete': 'Delete', 'station.relay': 'Relay', 'station.on': 'ON', 'station.off': 'OFF', 'station.type': 'Device type', 'station.name': 'Name', 'station.host': 'Host / IP', 'station.user': 'Username', 'station.pass': 'Password', 'station.optional': 'optional', 'station.labels': 'Relay labels', 'station.cancel': 'Cancel', 'station.save': 'Save',
   'sec.awards': 'Awards', 'sec.cat': 'CAT interface', 'sec.rotator': 'Rotator', 'sec.winkeyer': 'CW Keyer',
   'sec.antenna': 'Ultrabeam / Steppir', 'sec.antgenius': 'Antenna Genius', 'sec.pgxl': 'Power Genius', 'sec.flex': 'FlexRadio', 'sec.audio': 'Audio devices',
+  'sec.relayauto': 'Relay auto-control',
+  'relayauto.hint': 'Automatically switch Station Control relays from the rig frequency / band (like PstRotator). Each relay: a frequency window (ON inside, OFF outside) or a set of bands. Relays are set up in the Station Control panel.',
+  'relayauto.enable': 'Enable relay auto-control',
+  'relayauto.noDevices': 'No relay board configured. Add one in the Station Control panel first.',
+  'relayauto.relay': 'Relay',
+  'relayauto.modeOff': 'Off (manual)', 'relayauto.modeFreq': 'Frequency', 'relayauto.modeBand': 'Band',
+  'relayauto.from': 'from', 'relayauto.to': 'to',
   // General panel
   'gen.hint': 'App behaviour (saved instantly).',
   'gen.autofocusWB': 'Auto-focus "Worked before" for known stations',
@@ -423,6 +430,13 @@ const fr: Dict = {
   'station.title': 'Contrôle station', 'station.rotator': 'Rotator', 'station.rotatorNoRead': 'Azimut non lu', 'station.pattern': 'Diagramme', 'station.bi': 'Bi', 'station.retract': 'Rétracter les éléments', 'station.moving': 'EN MOUVEMENT', 'station.elements': 'Éléments (mm)', 'station.read': 'Lire', 'station.readLengths': 'Lire les longueurs actuelles depuis le contrôleur', 'station.noLengths': 'Longueurs inconnues — clique sur Lire pour les récupérer depuis le contrôleur.', 'station.element': 'Élément', 'station.reflector': 'Réflecteur', 'station.driven': 'Radiateur', 'station.director': 'Dir', 'station.set': 'Régler', 'station.elementsHint': "Chaque appui allonge/raccourcit l'élément de 2 mm (comme le pupitre). Vérifie quel élément répond sur ton antenne.", 'station.setExactLen': "Clique pour taper la longueur actuelle exacte (recale la base si la lecture auto est fausse).", 'station.atMax': "Refusé par le contrôleur — l'élément est probablement en butée (longueur max pour cette bande), il ne peut plus s'allonger.", 'station.go': 'Aller', 'station.stop': 'Stop', 'station.dragHint': 'Glisse une carte pour réordonner. Choisis un nombre de colonnes pour la disposition.', 'station.colsAuto': 'Auto', 'station.addDevice': 'Ajouter un appareil', 'station.editDevice': "Modifier l'appareil", 'station.empty': "Aucune carte relais. Ajoute un WebSwitch 1216H ou une carte KMTronic 8 relais pour piloter l'alimentation et les accessoires de ta station.", 'station.online': 'En ligne', 'station.offline': 'Hors ligne', 'station.edit': 'Modifier', 'station.delete': 'Supprimer', 'station.relay': 'Relais', 'station.on': 'ON', 'station.off': 'OFF', 'station.type': "Type d'appareil", 'station.name': 'Nom', 'station.host': 'Hôte / IP', 'station.user': "Nom d'utilisateur", 'station.pass': 'Mot de passe', 'station.optional': 'optionnel', 'station.labels': 'Libellés des relais', 'station.cancel': 'Annuler', 'station.save': 'Enregistrer',
   'sec.awards': 'Diplômes', 'sec.cat': 'Interface CAT', 'sec.rotator': 'Rotator', 'sec.winkeyer': 'Manipulateur CW',
   'sec.antenna': 'Antenne motorisée', 'sec.antgenius': 'Antenna Genius', 'sec.pgxl': 'Power Genius', 'sec.flex': 'FlexRadio', 'sec.audio': 'Périphériques audio',
+  'sec.relayauto': 'Relais automatiques',
+  'relayauto.hint': "Commute automatiquement les relais du Station Control selon la fréquence / bande du poste (comme PstRotator). Par relais : une plage de fréquence (ON dedans, OFF dehors) ou un ensemble de bandes. Les relais se configurent dans le panneau Station Control.",
+  'relayauto.enable': 'Activer les relais automatiques',
+  'relayauto.noDevices': "Aucune carte relais configurée. Ajoutes-en une dans le panneau Station Control d'abord.",
+  'relayauto.relay': 'Relais',
+  'relayauto.modeOff': 'Off (manuel)', 'relayauto.modeFreq': 'Fréquence', 'relayauto.modeBand': 'Bande',
+  'relayauto.from': 'de', 'relayauto.to': 'à',
   'gen.hint': 'Comportement de l\'application (enregistré immédiatement).',
   'gen.autofocusWB': 'Focus auto sur « Déjà contacté » pour les stations connues',
   'gen.showBeam': 'Afficher le cap de l\'antenne sur la carte principale',