feat(server): add nest AppConfigModule bound to @nestjs/config

server/src/nest/app-config/app-config.module.ts

@@ -0,0 +1,38 @@
+/**
+ * Global binding of @nestjs/config onto TREK's app-config layer.
+ *
+ * INVARIANTS — breaking either silently breaks ~60 env-mutating tests:
+ *  - `cache: false`, always. `cache: true` would freeze ConfigService lookups
+ *    for the whole app lifetime; the runtime-toggled vars (DEMO_MODE, NODE_ENV,
+ *    OIDC_*, …) must stay live via RuntimeEnvService/readEnv().
+ *  - No `validate`/`validationSchema` here. Fail-fast validation runs exactly
+ *    once, from the production entrypoint (src/app-config/boot-validate.ts) —
+ *    buildApp() is invoked dozens of times per test run and must stay
+ *    side-effect-free.
+ *  - `ignoreEnvFile: true`, always. dotenv is loaded ONCE in index.ts; tests
+ *    deliberately never load .env, and reading it here would leak a
+ *    developer's local server/.env into every integration test.
+ *
+ * The framework's ConfigModule is aliased ONLY inside this file: app.module.ts
+ * already imports a local `ConfigModule` (the /api/config endpoint module), so
+ * the alias keeps the two from colliding anywhere else.
+ */
+import { Global, Module } from '@nestjs/common';
+import { ConfigModule as NestConfigModule } from '@nestjs/config';
+import { BOOT_STABLE_TOKENS } from './tokens';
+import { RuntimeEnvService } from './runtime-env.service';
+
+@Global()
+@Module({
+  imports: [
+    NestConfigModule.forRoot({
+      isGlobal: true,
+      ignoreEnvFile: true,
+      cache: false,
+      load: BOOT_STABLE_TOKENS,
+    }),
+  ],
+  providers: [RuntimeEnvService],
+  exports: [RuntimeEnvService],
+})
+export class AppConfigModule {}

server/src/nest/app-config/index.ts

@@ -0,0 +1,13 @@
+export { AppConfigModule } from './app-config.module';
+export { RuntimeEnvService } from './runtime-env.service';
+export {
+  httpConfig,
+  sessionConfig,
+  mcpConfig,
+  integrationsConfig,
+  backupConfig,
+  dbConfig,
+  pathsConfig,
+  netConfig,
+  BOOT_STABLE_TOKENS,
+} from './tokens';

server/src/nest/app-config/runtime-env.service.ts

@@ -0,0 +1,45 @@
+import { Injectable } from '@nestjs/common';
+import { readEnv, type AppEnv } from '../../app-config';
+
+/**
+ * DI-friendly access to the RUNTIME-TOGGLED env values (DEMO_MODE, NODE_ENV,
+ * APP_VERSION, OIDC_*, …). Every method delegates to readEnv() at call time —
+ * never snapshot a namespace into a field or the constructor, or the ~60 tests
+ * that mutate process.env mid-lifetime break.
+ *
+ * Boot-stable values are NOT accessed through this service; inject their
+ * registerAs token instead (see tokens.ts).
+ */
+@Injectable()
+export class RuntimeEnvService {
+  /** The full live-derived env — prefer the convenience getters where one exists. */
+  env(): AppEnv {
+    return readEnv();
+  }
+
+  isDemoMode(): boolean {
+    return readEnv().demo.enabled;
+  }
+
+  nodeEnv(): string | undefined {
+    return readEnv().app.nodeEnv;
+  }
+
+  isProduction(): boolean {
+    return readEnv().app.isProduction;
+  }
+
+  isDevelopment(): boolean {
+    return readEnv().app.isDevelopment;
+  }
+
+  /** Raw APP_VERSION — call sites keep their own fallback ('0.0.0' vs package.json vs semver). */
+  appVersion(): string | undefined {
+    return readEnv().app.appVersion;
+  }
+
+  /** Raw APP_URL — call sites keep their own trailing-slash handling. */
+  appUrl(): string | undefined {
+    return readEnv().app.appUrl;
+  }
+}

server/src/nest/app-config/tokens.ts

@@ -0,0 +1,50 @@
+/**
+ * registerAs tokens over the app-config derive functions, for the BOOT-STABLE
+ * namespaces only (see src/app-config/README.md for the classification).
+ *
+ * A token's factory runs during NestFactory.create(), so the injected object is
+ * a SNAPSHOT per built app — integration tests that mutate env and then rebuild
+ * buildApp() get fresh values automatically. Runtime-toggled values (DEMO_MODE,
+ * NODE_ENV, OIDC_*, …) must NOT get tokens here; they go through
+ * RuntimeEnvService / readEnv() so mid-lifetime env mutations stay visible.
+ *
+ * Consumption pattern:
+ *   constructor(@Inject(httpConfig.KEY) private readonly http: ConfigType<typeof httpConfig>) {}
+ */
+import { registerAs } from '@nestjs/config';
+import {
+  deriveBackup,
+  deriveDb,
+  deriveHttp,
+  deriveIntegrations,
+  deriveMcp,
+  deriveNet,
+  derivePaths,
+  deriveSession,
+} from '../../app-config';
+
+/**
+ * http is snapshot-consumed only by the pre-init Express layer (bootstrap
+ * threads it into applyGlobalMiddleware) — apply-time freeze per built app.
+ * Request-time reads of the same vars (cookie.ts FORCE_HTTPS checks) stay live
+ * via readEnv().
+ */
+export const httpConfig = registerAs('http', () => deriveHttp(process.env));
+export const sessionConfig = registerAs('session', () => deriveSession(process.env));
+export const mcpConfig = registerAs('mcp', () => deriveMcp(process.env));
+export const integrationsConfig = registerAs('integrations', () => deriveIntegrations(process.env));
+export const backupConfig = registerAs('backup', () => deriveBackup(process.env));
+export const dbConfig = registerAs('db', () => deriveDb(process.env));
+export const pathsConfig = registerAs('paths', () => derivePaths(process.env));
+export const netConfig = registerAs('net', () => deriveNet(process.env));
+
+export const BOOT_STABLE_TOKENS = [
+  httpConfig,
+  sessionConfig,
+  mcpConfig,
+  integrationsConfig,
+  backupConfig,
+  dbConfig,
+  pathsConfig,
+  netConfig,
+];

server/src/nest/app.module.ts

@@ -1,5 +1,6 @@
 import { Module } from '@nestjs/common';
 import { APP_FILTER, APP_INTERCEPTOR } from '@nestjs/core';
+import { AppConfigModule } from './app-config/app-config.module';
 import { DatabaseModule } from './database/database.module';
 import { HealthController } from './health/health.controller';
 import { HealthService } from './health/health.service';
@@ -52,7 +53,7 @@ import { IdempotencyInterceptor } from './common/idempotency.interceptor';
  * migrated.
  */
 @Module({
-  imports: [DatabaseModule, WeatherModule, HelpModule, AirportsModule, ConfigModule, SystemNoticesModule, MapsModule, CategoriesModule, TagsModule, NotificationsModule, AtlasModule, VacayModule, PackingModule, TodoModule, BudgetModule, ReservationsModule, DaysModule, AssignmentsModule, PlacesModule, TripsModule, CollabModule, FilesModule, PhotosModule, MemoriesModule, AirtrailModule, JourneyModule, CollectionsModule, ShareModule, TripInviteModule, TransitModule, FeedsModule, SettingsModule, BackupModule, AuthModule, OidcModule, OauthModule, AdminModule, AddonsModule, PluginsModule, BookingImportModule],
+  imports: [AppConfigModule, DatabaseModule, WeatherModule, HelpModule, AirportsModule, ConfigModule, SystemNoticesModule, MapsModule, CategoriesModule, TagsModule, NotificationsModule, AtlasModule, VacayModule, PackingModule, TodoModule, BudgetModule, ReservationsModule, DaysModule, AssignmentsModule, PlacesModule, TripsModule, CollabModule, FilesModule, PhotosModule, MemoriesModule, AirtrailModule, JourneyModule, CollectionsModule, ShareModule, TripInviteModule, TransitModule, FeedsModule, SettingsModule, BackupModule, AuthModule, OidcModule, OauthModule, AdminModule, AddonsModule, PluginsModule, BookingImportModule],
   controllers: [HealthController],
   providers: [
     HealthService,