Phase 6: Translate User Pages - exchange, trades, invites, profile

- Expand exchange.json with all exchange page strings (page, steps, detailsStep, bookingStep, confirmationStep, priceDisplay)
- Create trades.json translation files for es, en, ca
- Create invites.json translation files for es, en, ca
- Create profile.json translation files for es, en, ca
- Translate exchange page and all components (ExchangeDetailsStep, BookingStep, ConfirmationStep, StepIndicator, PriceDisplay)
- Translate trades page (titles, sections, buttons, status labels)
- Translate invites page (titles, sections, status badges, copy button)
- Translate profile page (form labels, hints, placeholders, messages)
- Update IntlProvider to load all new namespaces
- All frontend tests passing

frontend/locales/en/exchange.json

@@ -8,10 +8,70 @@
   },
   "direction": {
     "buy": "BUY BTC",
-    "sell": "SELL BTC"
+    "sell": "SELL BTC",
+    "buyShort": "Buy BTC",
+    "sellShort": "Sell BTC"
   },
   "transferMethod": {
     "onchain": "Onchain",
     "lightning": "Lightning"
+  },
+  "page": {
+    "title": "Exchange Bitcoin",
+    "subtitle": "Buy or sell Bitcoin with a 5% premium",
+    "viewExistingTrade": "View your existing trade →"
+  },
+  "steps": {
+    "details": "Exchange Details",
+    "booking": "Book Appointment",
+    "confirm": "Confirm"
+  },
+  "detailsStep": {
+    "paymentMethod": "Payment Method",
+    "required": "*",
+    "lightningThreshold": "Lightning payments are only available for amounts up to €{max}",
+    "amount": "Amount (EUR)",
+    "summaryBuy": "You buy {sats}, you sell {eur}",
+    "summarySell": "You buy {eur}, you sell {sats}",
+    "continueToBooking": "Continue to Booking"
+  },
+  "bookingStep": {
+    "yourExchange": "Your Exchange",
+    "edit": "Edit",
+    "buy": "Buy",
+    "sell": "Sell",
+    "receiveVia": "Receive via",
+    "sendVia": "Send via",
+    "selectDate": "Select a Date",
+    "existingTradeWarning": "You already have a trade booked on this day. You can only book one trade per day.",
+    "viewExistingTrade": "View your existing trade →",
+    "availableSlots": "Available Slots for",
+    "loadingSlots": "Loading slots...",
+    "noSlots": "No available slots for this date"
+  },
+  "confirmationStep": {
+    "appointment": "Appointment",
+    "edit": "Edit",
+    "confirmTrade": "Confirm Trade",
+    "time": "Time:",
+    "direction": "Direction:",
+    "eur": "EUR:",
+    "btc": "BTC:",
+    "rate": "Rate:",
+    "payment": "Payment:",
+    "receiveVia": "Receive via",
+    "sendVia": "Send via",
+    "booking": "Booking...",
+    "priceStale": "Price Stale",
+    "confirmBuy": "Confirm Buy",
+    "confirmSell": "Confirm Sell",
+    "back": "Back"
+  },
+  "priceDisplay": {
+    "loading": "Loading price...",
+    "market": "Market:",
+    "ourPrice": "Our price:",
+    "updated": "Updated",
+    "stale": "(stale)"
   }
 }