feat(blockchain): wire BlockchainModule into dependent modules

backend/.env.example

@@ -27,3 +27,9 @@ MAIL_USER=your-email@gmail.com
 MAIL_PASSWORD=your-app-password
 MAIL_FROM_NAME=MindBlock
 MAIL_FROM_ADDRESS=noreply@mindblock.com
+
+# Stellar / Soroban configuration (BlockchainModule)
+STELLAR_SECRET_KEY=your-stellar-secret-key
+STELLAR_CONTRACT_ID=your-soroban-contract-id
+STELLAR_RPC_URL=https://soroban-testnet.stellar.org
+STELLAR_NETWORK_PASSPHRASE=Test SDF Network ; September 2015

backend/src/blockchain/blockchain.module.spec.ts

@@ -0,0 +1,48 @@
+import { Test, TestingModule } from '@nestjs/testing';
+import { EventEmitterModule } from '@nestjs/event-emitter';
+import { BlockchainModule } from './blockchain.module';
+import { BlockchainService } from './provider/blockchain.service';
+import { ProgressModule } from '../progress/progress.module';
+import { UsersModule } from '../users/users.module';
+import { QuestsModule } from '../quests/quests.module';
+
+const metadataArrayOf = (key: 'imports' | 'providers', target: object) =>
+  (Reflect.getMetadata(key, target) as unknown[] | undefined) ?? [];
+
+describe('BlockchainModule wiring', () => {
+  it('provides and exports BlockchainService', async () => {
+    const module: TestingModule = await Test.createTestingModule({
+      imports: [EventEmitterModule.forRoot(), BlockchainModule],
+    }).compile();
+
+    expect(module.get(BlockchainService, { strict: false })).toBeInstanceOf(
+      BlockchainService,
+    );
+  });
+
+  it('is imported by ProgressModule', () => {
+    expect(metadataArrayOf('imports', ProgressModule)).toContain(
+      BlockchainModule,
+    );
+  });
+
+  it('is imported by UsersModule', () => {
+    expect(metadataArrayOf('imports', UsersModule)).toContain(BlockchainModule);
+  });
+
+  it('is imported by QuestsModule', () => {
+    expect(metadataArrayOf('imports', QuestsModule)).toContain(
+      BlockchainModule,
+    );
+  });
+
+  it('does not re-export consumers as service providers', () => {
+    // BlockchainService must come through the BlockchainModule import,
+    // never be listed directly in a consumer's own providers array.
+    for (const consumer of [ProgressModule, UsersModule, QuestsModule]) {
+      expect(metadataArrayOf('providers', consumer)).not.toContain(
+        BlockchainService,
+      );
+    }
+  });
+});

backend/src/blockchain/blockchain.module.ts

@@ -1,10 +1,29 @@
 import { Module } from '@nestjs/common';
+import { ConfigModule } from '@nestjs/config';
+import stellarConfig from '../config/stellar.config';
 import { BlockchainController } from './controller/blockchain.controller';
 import { BlockchainService } from './provider/blockchain.service';
 
+/**
+ * Registers the blockchain providers and exports BlockchainService so any
+ * importing module (ProgressModule, UsersModule, QuestsModule, ...) can
+ * inject it to trigger on-chain actions.
+ *
+ * STELLAR_SECRET_KEY, STELLAR_CONTRACT_ID, STELLAR_RPC_URL and
+ * STELLAR_NETWORK_PASSPHRASE are exposed through the namespaced
+ * `stellar` configuration registered below (see src/config/stellar.config.ts).
+ */
 @Module({
+  imports: [ConfigModule.forFeature(stellarConfig)],
   controllers: [BlockchainController],
-  providers: [BlockchainService],
+  providers: [
+    // On-chain action providers land with issues 11-14:
+    //   RegisterPlayerProvider, SubmitPuzzleProvider, GetPlayerProvider,
+    //   SyncXpMilestoneProvider. Each must be added to this array (and the
+    //   matching method on BlockchainService) as soon as it is merged so
+    //   they are injectable alongside BlockchainService.
+    BlockchainService,
+  ],
   exports: [BlockchainService],
 })
 export class BlockchainModule {}

backend/src/config/stellar.config.ts

@@ -0,0 +1,17 @@
+import { registerAs } from '@nestjs/config';
+
+/**
+ * Stellar/Soroban on-chain configuration.
+ *
+ * Loaded through `ConfigModule.forFeature(stellarConfig)` inside
+ * BlockchainModule so every blockchain provider can resolve these values
+ * via `ConfigService.get('stellar')` without reaching for `process.env`.
+ */
+export default registerAs('stellar', () => ({
+  secretKey: process.env.STELLAR_SECRET_KEY,
+  contractId: process.env.STELLAR_CONTRACT_ID,
+  rpcUrl: process.env.STELLAR_RPC_URL || 'https://soroban-testnet.stellar.org',
+  networkPassphrase:
+    process.env.STELLAR_NETWORK_PASSPHRASE ||
+    'Test SDF Network ; September 2015',
+}));

backend/src/progress/progress.module.ts

@@ -13,10 +13,14 @@ import { ProgressCalculationProvider } from './providers/progress-calculation.pr
 import { Puzzle } from '../puzzles/entities/puzzle.entity';
 import { XpLevelService } from '../users/providers/xp-level.service';
 import { ScoreService } from '../score/providers/score.service';
+import { BlockchainModule } from '../blockchain/blockchain.module';
 
 @Module({
   imports: [
     TypeOrmModule.forFeature([UserProgress, User, Puzzle, Streak, DailyQuest]),
+    // BlockchainService is needed by ProgressCalculationProvider for
+    // submitPuzzleOnChain after puzzle answer verification.
+    BlockchainModule,
   ],
   controllers: [ProgressController],
   providers: [

backend/src/quests/quests.module.ts

@@ -11,6 +11,7 @@ import { PuzzlesModule } from '../puzzles/puzzles.module';
 import { ProgressModule } from '../progress/progress.module';
 import { UsersModule } from '../users/users.module';
 import { StreakModule } from '../streak/strerak.module';
+import { BlockchainModule } from '../blockchain/blockchain.module';
 
 @Module({
   imports: [
@@ -19,6 +20,9 @@ import { StreakModule } from '../streak/strerak.module';
     ProgressModule,
     UsersModule,
     StreakModule,
+    // BlockchainService is needed by CompleteDailyQuestProvider for
+    // syncXpMilestone after the daily quest completion bonus XP is awarded.
+    BlockchainModule,
   ],
   controllers: [DailyQuestController],
   providers: [

backend/src/users/users.module.ts

@@ -17,12 +17,16 @@ import { UserProgress } from '../progress/entities/progress.entity';
 import { Streak } from '../streak/entities/streak.entity';
 import { DailyQuest } from '../quests/entities/daily-quest.entity';
 import { XpLevelService } from './providers/xp-level.service';
+import { BlockchainModule } from '../blockchain/blockchain.module';
 
 @Module({
   imports: [
     forwardRef(() => AuthModule),
     TypeOrmModule.forFeature([User, UserProgress, Streak, DailyQuest]),
     PaginationModule,
+    // BlockchainService is needed by the wallet-linking onboarding flow
+    // (registerPlayerOnChain) and for syncXpMilestone after level-up.
+    BlockchainModule,
   ],
   controllers: [UsersController],
   providers: [