feat(i18n): install react-i18next, create English locale files, and initialize i18n framework

- Install i18next, react-i18next, i18next-browser-languagedetector
- Create 6 namespace JSON files (common, collection, threads, setups, onboarding, settings)
- Initialize i18n with language detection (localStorage + navigator)
- Wire i18n import in main.tsx before React rendering

Phase 34, Plan 01

src/client/locales/en/collection.json

@@ -0,0 +1,31 @@
+{
+	"title": "Collection",
+	"gear": "Gear",
+	"planning": "Planning",
+	"empty": {
+		"title": "Your collection is empty",
+		"description": "Start cataloging your gear by adding your first item. Track weight, price, and organize by category.",
+		"addFirst": "Add your first item"
+	},
+	"form": {
+		"name": "Name",
+		"nameRequired": "Name *",
+		"namePlaceholder": "e.g. Osprey Talon 22",
+		"weight": "Weight (g)",
+		"weightPlaceholder": "e.g. 680",
+		"price": "Price ($)",
+		"pricePlaceholder": "e.g. 129.99",
+		"quantity": "Quantity",
+		"category": "Category",
+		"notes": "Notes",
+		"notesPlaceholder": "Any additional notes...",
+		"productLink": "Product Link",
+		"urlPlaceholder": "https://..."
+	},
+	"classification": {
+		"ultralight": "Ultralight",
+		"light": "Light",
+		"medium": "Medium",
+		"heavy": "Heavy"
+	}
+}