one source of truth for Route/Activity shapes; enforce api contracts

Route and Activity existed three times: hand-written interfaces in
packages/types, Zod contracts in packages/api, and Drizzle columns in
packages/db — each with different fields and nullability. The
hand-written ones had drifted so far they had zero importers; the Zod
contracts were advisory because v1 handlers hand-rolled Response.json
shapes nothing validated.

- packages/types keeps only what both apps actually share (Waypoint,
  WaypointPoiTags) and documents where row types and wire contracts
  live; the dead Route/RouteMetadata/RouteVersion/Activity interfaces
  are gone
- packages/db exports canonical inferred row types (RouteRow,
  ActivityRow, RouteVersionRow, UserRow)
- packages/api contracts are reconciled with the real wire format
  (RouteVersionSchema gains the id and createdBy fields the endpoint
  has always returned) and gain Create*ResponseSchemas
- apiJson(schema, payload) in api-guard parses every v1 response
  through its contract: drift is now a thrown ZodError in tests/CI,
  unknown keys are stripped, and payloads are compile-checked as
  z.input of the schema

Enforcement immediately caught two real drifts: nullable DB
descriptions could ship null where the contract promises string (now
coalesced at the boundary), and GET /api/v1/activities/:id was missing
the routeName and photos fields its contract declares.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

packages/db/src/schema/journal.ts

@@ -463,3 +463,13 @@ export const consumedJwtJti = journalSchema.table("consumed_jwt_jti", {
   // Sweep runs `DELETE WHERE expires_at < now()` on a daily schedule.
   expiresAtIdx: index("consumed_jwt_jti_expires_at_idx").on(t.expiresAt),
 }));
+
+// ---------------------------------------------------------------------------
+// Canonical row types — derive from the schema, never re-declare by hand.
+// API wire shapes live in @trails-cool/api; these are the database truth.
+// ---------------------------------------------------------------------------
+
+export type RouteRow = typeof routes.$inferSelect;
+export type RouteVersionRow = typeof routeVersions.$inferSelect;
+export type ActivityRow = typeof activities.$inferSelect;
+export type UserRow = typeof users.$inferSelect;