Add @trails-cool/api package with Zod schemas for REST API contract

Single source of truth for the Journal REST API:
- API_VERSION semver constant (1.0.0)
- Endpoint path constants (routes, activities, auth, uploads, push)
- Zod schemas for all request/response shapes:
  - Routes: list, detail, create, update, compute
  - Activities: list, detail, create
  - Auth: token exchange, refresh, device management
  - Discovery: instance info + API version
  - Uploads: presigned URL flow
  - Errors: structured error response with field-level details
- Cursor-based pagination schemas
- TypeScript types inferred from Zod (z.infer)

Used by Journal server (validation) and mobile client (type safety).

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

packages/api/src/routes.ts

@@ -0,0 +1,73 @@
+import { z } from "zod";
+
+/** Route summary for list views */
+export const RouteSummarySchema = z.object({
+  id: z.string().uuid(),
+  name: z.string(),
+  description: z.string(),
+  distance: z.number().nullable(),
+  elevationGain: z.number().nullable(),
+  elevationLoss: z.number().nullable(),
+  routingProfile: z.string().nullable(),
+  dayBreaks: z.array(z.number()),
+  geojson: z.string().nullable(),
+  createdAt: z.string().datetime(),
+  updatedAt: z.string().datetime(),
+});
+
+/** Route version info */
+export const RouteVersionSchema = z.object({
+  version: z.number(),
+  changeDescription: z.string().nullable(),
+  createdAt: z.string().datetime(),
+});
+
+/** Full route detail */
+export const RouteDetailSchema = RouteSummarySchema.extend({
+  gpx: z.string().nullable(),
+  versions: z.array(RouteVersionSchema),
+});
+
+/** Paginated route list response */
+export const RouteListResponseSchema = z.object({
+  routes: z.array(RouteSummarySchema),
+  nextCursor: z.string().nullable(),
+});
+
+/** Create route request */
+export const CreateRouteRequestSchema = z.object({
+  name: z.string().min(1).max(200),
+  description: z.string().max(5000).default(""),
+  gpx: z.string().optional(),
+  routingProfile: z.string().optional(),
+});
+
+/** Update route request */
+export const UpdateRouteRequestSchema = z.object({
+  name: z.string().min(1).max(200).optional(),
+  description: z.string().max(5000).optional(),
+  gpx: z.string().optional(),
+});
+
+/** Compute route request (BRouter proxy) */
+export const ComputeRouteRequestSchema = z.object({
+  waypoints: z.array(z.object({
+    lat: z.number(),
+    lon: z.number(),
+  })).min(2),
+  profile: z.string().default("fastbike"),
+  noGoAreas: z.array(z.object({
+    points: z.array(z.object({
+      lat: z.number(),
+      lon: z.number(),
+    })),
+  })).optional(),
+});
+
+export type RouteSummary = z.infer<typeof RouteSummarySchema>;
+export type RouteVersion = z.infer<typeof RouteVersionSchema>;
+export type RouteDetail = z.infer<typeof RouteDetailSchema>;
+export type RouteListResponse = z.infer<typeof RouteListResponseSchema>;
+export type CreateRouteRequest = z.infer<typeof CreateRouteRequestSchema>;
+export type UpdateRouteRequest = z.infer<typeof UpdateRouteRequestSchema>;
+export type ComputeRouteRequest = z.infer<typeof ComputeRouteRequestSchema>;