fix: remove slippage from realunit sell flow

src/integration/blockchain/realunit/__tests__/realunit-blockchain.service.spec.ts

@@ -90,42 +90,12 @@ describe('RealUnitBlockchainService', () => {
   });
 
   describe('getBrokerbotSellPrice', () => {
-    it('should query BrokerBot contract and apply default 0.5% slippage', async () => {
+    it('should query BrokerBot contract and return exact amount', async () => {
       // BrokerBot returns 1000 ZCHF (in Wei) for 10 shares
       mockReadContract.mockResolvedValue(BigInt('1000000000000000000000'));
 
       const result = await service.getBrokerbotSellPrice(MOCK_BROKERBOT_ADDRESS, 10);
 
-      // 1000 ZCHF * (1 - 0.005) = 995 ZCHF
-      expect(result.zchfAmountWei).toBe(BigInt('995000000000000000000'));
-    });
-
-    it('should calculate correctly for 1 share', async () => {
-      // BrokerBot returns 100 ZCHF for 1 share
-      mockReadContract.mockResolvedValue(BigInt('100000000000000000000'));
-
-      const result = await service.getBrokerbotSellPrice(MOCK_BROKERBOT_ADDRESS, 1);
-
-      // 100 * 0.995 = 99.5 ZCHF
-      expect(result.zchfAmountWei).toBe(BigInt('99500000000000000000'));
-    });
-
-    it('should accept custom slippage in basis points', async () => {
-      // BrokerBot returns 1000 ZCHF for 10 shares
-      mockReadContract.mockResolvedValue(BigInt('1000000000000000000000'));
-
-      const result = await service.getBrokerbotSellPrice(MOCK_BROKERBOT_ADDRESS, 10, 100); // 1% slippage
-
-      // 1000 * (1 - 0.01) = 990 ZCHF
-      expect(result.zchfAmountWei).toBe(BigInt('990000000000000000000'));
-    });
-
-    it('should handle zero slippage', async () => {
-      mockReadContract.mockResolvedValue(BigInt('1000000000000000000000'));
-
-      const result = await service.getBrokerbotSellPrice(MOCK_BROKERBOT_ADDRESS, 10, 0);
-
-      // Full amount with no slippage
       expect(result.zchfAmountWei).toBe(BigInt('1000000000000000000000'));
     });
 

src/integration/blockchain/realunit/realunit-blockchain.service.ts

@@ -130,11 +130,7 @@ export class RealUnitBlockchainService {
     };
   }
 
-  async getBrokerbotSellPrice(
-    brokerbotAddress: string,
-    shares: number,
-    slippageBps = 50,
-  ): Promise<{ zchfAmountWei: bigint }> {
+  async getBrokerbotSellPrice(brokerbotAddress: string, shares: number): Promise<{ zchfAmountWei: bigint }> {
     const blockchain = [Environment.DEV, Environment.LOC].includes(GetConfig().environment)
       ? Blockchain.SEPOLIA
       : Blockchain.ETHEREUM;
@@ -150,21 +146,17 @@ export class RealUnitBlockchainService {
     });
 
     // Call getSellPrice on the BrokerBot contract
-    const sellPriceWei = (await publicClient.readContract({
+    const zchfAmountWei = (await publicClient.readContract({
       address: brokerbotAddress as `0x${string}`,
       abi: BROKERBOT_ABI,
       functionName: 'getSellPrice',
       args: [BigInt(shares)],
     } as any)) as bigint;
 
-    if (sellPriceWei === 0n) {
+    if (zchfAmountWei === 0n) {
       throw new Error('BrokerBot returned zero sell price');
     }
 
-    // Apply slippage buffer (reduce expected amount to account for price movement)
-    const slippageFactor = BigInt(10000 - slippageBps);
-    const zchfAmountWei = (sellPriceWei * slippageFactor) / BigInt(10000);
-
     return { zchfAmountWei };
   }
 }

src/subdomains/supporting/realunit/realunit.service.ts

@@ -980,7 +980,8 @@ export class RealUnitService {
         throw new BadRequestException('Delegation delegator does not match user address');
       }
 
-      // Calculate expected ZCHF amount from BrokerBot (with slippage buffer)
+      // Calculate expected ZCHF amount from BrokerBot
+      // If price drops between quote and execution, transaction reverts safely and user can retry
       const [{ zchfAmountWei }, zchfAsset] = await Promise.all([
         this.blockchainService.getBrokerbotSellPrice(this.getBrokerbotAddress(), Math.floor(request.amount)),
         this.getZchfAsset(),