feat: add isolated lending pair foundation and Stellar fee oracle

client/src/pages/governance/TransactionBuilder.tsx

@@ -15,6 +15,21 @@ const RPC_URL =
 const NETWORK_PASSPHRASE =
   import.meta.env.VITE_NETWORK_PASSPHRASE ?? "Test SDF Network ; September 2015";
 
+async function getRecommendedBaseFee(): Promise<string> {
+  try {
+    const response = await fetch("/api/fees");
+    if (!response.ok) return StellarSdk.BASE_FEE;
+    const payload = (await response.json()) as {
+      fees?: { average?: number };
+    };
+    const fee = payload.fees?.average;
+    if (!fee || !Number.isFinite(fee) || fee <= 0) return StellarSdk.BASE_FEE;
+    return String(Math.round(fee));
+  } catch {
+    return StellarSdk.BASE_FEE;
+  }
+}
+
 export default function TransactionBuilder({
   threshold,
   contractId,
@@ -38,6 +53,7 @@ export default function TransactionBuilder({
       const server = new StellarSdk.rpc.Server(RPC_URL);
       const contract = new StellarSdk.Contract(contractId);
       const source = await server.getAccount(walletAddress);
+      const baseFee = await getRecommendedBaseFee();
 
       // Build ScVal args: admin address + action-specific fields
       const args: StellarSdk.xdr.ScVal[] = [
@@ -61,7 +77,7 @@ export default function TransactionBuilder({
       }
 
       const tx = new StellarSdk.TransactionBuilder(source, {
-        fee: StellarSdk.BASE_FEE,
+        fee: baseFee,
         networkPassphrase: NETWORK_PASSPHRASE,
       })
         .addOperation(contract.call(action.method, ...args))

client/src/services/soroban.ts

@@ -19,6 +19,12 @@ const ZAP_CONTRACT_ID = import.meta.env.VITE_ZAP_CONTRACT_ID ?? "";
 const POLL_INTERVAL_MS = 2_000;
 const POLL_TIMEOUT_MS = 30_000;
 
+type FeePriority = "low" | "average" | "high";
+
+interface FeeOraclePayload {
+  fees?: Partial<Record<FeePriority, number>>;
+}
+
 // ── Types ───────────────────────────────────────────────────────────────
 
 export interface TxResult {
@@ -35,6 +41,23 @@ function getServer(): StellarSdk.rpc.Server {
   return new StellarSdk.rpc.Server(RPC_URL);
 }
 
+async function getRecommendedBaseFee(priority: FeePriority = "average"): Promise<string> {
+  try {
+    const response = await fetch("/api/fees");
+    if (!response.ok) {
+      return StellarSdk.BASE_FEE;
+    }
+    const payload = (await response.json()) as FeeOraclePayload;
+    const fee = payload.fees?.[priority];
+    if (!fee || !Number.isFinite(fee) || fee <= 0) {
+      return StellarSdk.BASE_FEE;
+    }
+    return String(Math.round(fee));
+  } catch {
+    return StellarSdk.BASE_FEE;
+  }
+}
+
 function getContract(): StellarSdk.Contract {
   if (!CONTRACT_ID) {
     throw new Error("VITE_CONTRACT_ID is not configured");
@@ -61,9 +84,10 @@ async function buildContractCallOn(
 ): Promise<string> {
   const server = getServer();
   const source = await server.getAccount(sourcePublicKey);
+  const baseFee = await getRecommendedBaseFee("average");
 
   const tx = new StellarSdk.TransactionBuilder(source, {
-    fee: StellarSdk.BASE_FEE,
+    fee: baseFee,
     networkPassphrase: NETWORK_PASSPHRASE,
   })
     .addOperation(contract.call(method, ...args))

contracts/Cargo.toml

@@ -1,6 +1,6 @@
 [workspace]
 resolver = "2"
-members = ["yield_vault", "zap", "options", "aa_recovery", "aa_factory", "settlement", "intent_swap", "dutch_auction", "liquid_staking", "emission_controller", "strategies/delta_neutral", "stableswap", "stealth_addresses", "merkle_distributor"]
+members = ["yield_vault", "zap", "options", "aa_recovery", "aa_factory", "settlement", "intent_swap", "dutch_auction", "liquid_staking", "emission_controller", "strategies/delta_neutral", "stableswap", "stealth_addresses", "merkle_distributor", "isolated_lending"]
 
 [profile.release]
 opt-level = "z"

contracts/isolated_lending/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "isolated_lending"
+version = "0.1.0"
+edition = "2021"
+
+[lib]
+crate-type = ["cdylib"]
+
+[dependencies]
+soroban-sdk = "22.0.0"
+
+[dev-dependencies]
+soroban-sdk = { version = "22.0.0", features = ["testutils"] }