Implement shared packages (tasks 2.1-2.6)

- @trails-cool/types: Route, Activity, Waypoint, RouteVersion, RouteMetadata
- @trails-cool/gpx: GPX parser (XML→waypoints/tracks/elevation) and generator
  with round-trip test, haversine distance, elevation gain/loss computation
- @trails-cool/map: MapView (Leaflet + OSM/OpenTopoMap/CyclOSM layer switcher),
  RouteLayer (GeoJSON polyline rendering)
- @trails-cool/ui: Button (primary/secondary/ghost), Input (with label/error),
  Card components with Tailwind styling
- @trails-cool/i18n: react-i18next config with English + German translations,
  browser language detection, fallback to English

All 13 unit tests pass. Both apps build successfully.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/i18n/package.json

@@ -2,6 +2,15 @@
   "name": "@trails-cool/i18n",
   "version": "0.0.1",
   "type": "module",
+  "exports": {
+    ".": "./src/index.ts",
+    "./locales/*": "./src/locales/*"
+  },
   "main": "./src/index.ts",
-  "types": "./src/index.ts"
+  "types": "./src/index.ts",
+  "peerDependencies": {
+    "react": ">=18",
+    "i18next": ">=23",
+    "react-i18next": ">=14"
+  }
 }

packages/i18n/src/index.ts

@@ -1,5 +1,29 @@
-/**
- * Shared i18n configuration and translation strings for trails.cool
- * Uses react-i18next. Start with English + German.
- */
-export {};
+import i18n from "i18next";
+import { initReactI18next } from "react-i18next";
+import LanguageDetector from "i18next-browser-languagedetector";
+import en from "./locales/en";
+import de from "./locales/de";
+
+export const defaultNS = "common";
+
+export const resources = {
+  en: { common: en.common, planner: en.planner, journal: en.journal },
+  de: { common: de.common, planner: de.planner, journal: de.journal },
+} as const;
+
+export function initI18n() {
+  return i18n
+    .use(LanguageDetector)
+    .use(initReactI18next)
+    .init({
+      resources,
+      defaultNS,
+      fallbackLng: "en",
+      supportedLngs: ["en", "de"],
+      interpolation: {
+        escapeValue: false,
+      },
+    });
+}
+
+export { i18n };

packages/i18n/src/locales/de.ts

@@ -0,0 +1,59 @@
+export default {
+  common: {
+    save: "Speichern",
+    cancel: "Abbrechen",
+    delete: "Löschen",
+    edit: "Bearbeiten",
+    close: "Schließen",
+    loading: "Wird geladen...",
+    error: "Etwas ist schiefgelaufen",
+  },
+  planner: {
+    title: "trails.cool Planer",
+    subtitle: "Gemeinsame Routenplanung",
+    newSession: "Neue Sitzung",
+    saveRoute: "Route speichern",
+    exportGpx: "GPX exportieren",
+    profile: "Routing-Profil",
+    profiles: {
+      trekking: "Wandern",
+      bike: "Radfahren",
+      shortest: "Kürzeste",
+    },
+    elevation: {
+      gain: "Höhenmeter aufwärts",
+      loss: "Höhenmeter abwärts",
+      profile: "Höhenprofil",
+    },
+  },
+  journal: {
+    title: "trails.cool",
+    subtitle: "Dein Outdoor-Aktivitäten-Tagebuch",
+    routes: {
+      title: "Routen",
+      new: "Neue Route",
+      edit: "Route bearbeiten",
+      editInPlanner: "Im Planer bearbeiten",
+      importGpx: "GPX importieren",
+      exportGpx: "GPX exportieren",
+      delete: "Route löschen",
+      distance: "Strecke",
+      elevationGain: "Höhenmeter",
+    },
+    activities: {
+      title: "Aktivitäten",
+      new: "Neue Aktivität",
+      duration: "Dauer",
+      linkToRoute: "Mit Route verknüpfen",
+      createRouteFromActivity: "Route aus Aktivität erstellen",
+    },
+    auth: {
+      login: "Anmelden",
+      register: "Registrieren",
+      logout: "Abmelden",
+      email: "E-Mail",
+      password: "Passwort",
+      username: "Benutzername",
+    },
+  },
+} as const;

packages/i18n/src/locales/en.ts

@@ -0,0 +1,59 @@
+export default {
+  common: {
+    save: "Save",
+    cancel: "Cancel",
+    delete: "Delete",
+    edit: "Edit",
+    close: "Close",
+    loading: "Loading...",
+    error: "Something went wrong",
+  },
+  planner: {
+    title: "trails.cool Planner",
+    subtitle: "Collaborative route planning",
+    newSession: "New Session",
+    saveRoute: "Save Route",
+    exportGpx: "Export GPX",
+    profile: "Routing Profile",
+    profiles: {
+      trekking: "Hiking",
+      bike: "Cycling",
+      shortest: "Shortest",
+    },
+    elevation: {
+      gain: "Elevation Gain",
+      loss: "Elevation Loss",
+      profile: "Elevation Profile",
+    },
+  },
+  journal: {
+    title: "trails.cool",
+    subtitle: "Your outdoor activity journal",
+    routes: {
+      title: "Routes",
+      new: "New Route",
+      edit: "Edit Route",
+      editInPlanner: "Edit in Planner",
+      importGpx: "Import GPX",
+      exportGpx: "Export GPX",
+      delete: "Delete Route",
+      distance: "Distance",
+      elevationGain: "Elevation Gain",
+    },
+    activities: {
+      title: "Activities",
+      new: "New Activity",
+      duration: "Duration",
+      linkToRoute: "Link to Route",
+      createRouteFromActivity: "Create Route from Activity",
+    },
+    auth: {
+      login: "Log In",
+      register: "Sign Up",
+      logout: "Log Out",
+      email: "Email",
+      password: "Password",
+      username: "Username",
+    },
+  },
+} as const;