refactor(server): decorate the weather, airport and transport MCP tools

Three of the four remaining hand-written registrars are gone. The tools keep
their names, descriptions, input schemas, annotations and result shapes; the
registration-time scope gates (`if (canWeather)`, `if (canGeo)`,
`if (!canWrite(scopes, 'reservations')) return`) become declarative access
markers, resolved by trekMcpAccessPolicy like every other decorated domain.

get_weather / get_detailed_weather move into a new WeatherMcp over the injected
WeatherService, including the catch that answers with the upstream message and
isError rather than throwing - a client sees "Weather service not available."
instead of a transport failure when the provider is down.

search_airports / get_airport move into a new AirportsMcp with no injected
service at all: the airport table is a static dataset. AirportsService owns the
flight-endpoint backfill against the database, which neither tool touches.

create/update/delete_transport move into ReservationsMcp rather than a domain of
their own, because a transport IS a reservation - same table, same service, same
reservation_edit permission - and that class already injects everything they
needed from the four bridges the registrar was importing.

That was budget.bridge's last outside-container consumer, so
linkBudgetItemToReservation is pruned with it; the file is down to one export and
dies as soon as BudgetMcp stops needing AuthService.

journey.ts stays: it still reaches into services/journeyService, which cannot
fold until memories does.

server/tests/helpers/mcp-test-controllers.ts

@@ -21,6 +21,9 @@ import { DayNotesService } from '../../src/nest/days/day-notes.service';
 import { DaysMcp } from '../../src/nest/days/days.mcp';
 import { DaysService } from '../../src/nest/days/days.service';
 import { MapsMcp } from '../../src/nest/maps/maps.mcp';
+import { WeatherMcp } from '../../src/nest/weather/weather.mcp';
+import { WeatherService } from '../../src/nest/weather/weather.service';
+import { AirportsMcp } from '../../src/nest/airports/airports.mcp';
 import { MapsService } from '../../src/nest/maps/maps.service';
 import { NotificationsMcp } from '../../src/nest/notifications/notifications.mcp';
 import { NotificationsService } from '../../src/nest/notifications/notifications.service';
@@ -89,6 +92,9 @@ export function createMcpTestRegistry(): McpRegistry {
     [
       new TagsMcp(new TagsService(dbService), authService),
       new CategoriesMcp(new CategoriesService(dbService)),
+      // The weather and airport tools left the legacy mapsWeather registrar.
+      new WeatherMcp(new WeatherService()),
+      new AirportsMcp(),
       new TodoMcp(todoService, authService),
       new PackingMcp(packingService, authService),
       new BudgetMcp(budgetService, exchangeRatesService, dbService, authService),