feat(backend): Implement graceful Stellar RPC error handling with ret…

LINTING_FIXES.md

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+# Linting Fixes Applied
+
+## Issues Found in CI
+
+### Error (1)
+**File**: `apps/backend/src/modules/escrow/services/escrow.service.ts`  
+**Line**: 297  
+**Issue**: Unsafe argument of type error typed assigned to a parameter of type `EscrowEventType`  
+**Error Code**: `@typescript-eslint/no-unsafe-argument`
+
+**Root Cause**: Missing closing parenthesis in `logEvent()` method call
+
+**Fix Applied**:
+```typescript
+// Before (missing closing parenthesis)
+await this.logEvent(
+  id,
+  EscrowEventType.EXPIRED,
+  userId,
+  {
+    reason: dto.reason || 'Deadline exceeded',
+    previousStatus: escrow.status,
+    expiresAt: escrow.expiresAt,
+    expiredAt: now,
+  },
+  ipAddress,
+
+// After (added closing parenthesis)
+await this.logEvent(
+  id,
+  EscrowEventType.EXPIRED,
+  userId,
+  {
+    reason: dto.reason || 'Deadline exceeded',
+    previousStatus: escrow.status,
+    expiresAt: escrow.expiresAt,
+    expiredAt: now,
+  },
+  ipAddress,
+);
+```
+
+### Warnings (5)
+**File**: `apps/backend/src/modules/escrow/services/escrow.service.spec.ts`  
+**Lines**: 397, 421, 509, 539, 566  
+**Issue**: Unsafe argument of type `any` assigned to a parameter of type `UpdateResult | Promise<UpdateResult>`  
+**Error Code**: `@typescript-eslint/no-unsafe-argument`
+
+**Root Cause**: Using `as any` type casting for UpdateResult mocks
+
+**Fix Applied**:
+```typescript
+// Before
+escrowRepository.update.mockResolvedValue({ affected: 1 } as any);
+
+// After
+escrowRepository.update.mockResolvedValue({ affected: 1 } as UpdateResult);
+```
+
+**Locations Fixed**:
+1. Line 393 - `fileDispute` test
+2. Line 419 - `fileDispute` by seller test
+3. Line 505 - `resolveDispute` with RELEASED_TO_SELLER test
+4. Line 530 - `resolveDispute` with CANCELLED test
+5. Line 556 - `resolveDispute` with SPLIT test
+
+## Verification
+
+✅ TypeScript diagnostics: No errors  
+✅ All type casts properly typed  
+✅ Syntax errors resolved  
+✅ Code follows TypeScript strict mode rules  
+
+## Commit Details
+
+**Commit**: d7bcb27  
+**Message**: "fix: resolve linting errors in escrow service"  
+**Files Changed**: 3  
+- `PR_DETAILS.md` (new)
+- `apps/backend/src/modules/escrow/services/escrow.service.spec.ts` (modified)
+- `apps/backend/src/modules/escrow/services/escrow.service.ts` (modified)
+
+## CI Status
+
+The fixes have been pushed to the `feature/deadline-enforcement` branch.  
+CI should now pass the linting checks.

PR_MESSAGE.md

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+# Add Secure Admin-Controlled Contract Upgrade (Safe Upgrade Pattern)
+
+## Summary
+
+This PR implements a secure, admin-controlled contract upgrade pattern ("Safe Upgrade" / Admin Proxy) for the VaultixEscrow Soroban contract. It allows protocol maintainers to fix bugs or add features without migrating all state and users to a new contract address.
+
+## Key Changes
+
+- **Upgrade Functionality:**  
+  - Added `upgrade(env, new_wasm_hash: [u8; 32])` to the contract, callable only by the admin.
+  - Emits a `ContractUpgraded` event before performing the upgrade.
+  - Enforces strict access control (admin-only).
+  - Documents storage compatibility requirements for future upgrades.
+
+- **Testing:**  
+  - Integration test verifies:
+    - State is preserved across upgrades.
+    - Unauthorized users cannot trigger upgrades.
+    - New contract logic is accessible after upgrade.
+
+## Motivation
+
+Soroban allows contract upgrades via `env.deployer().update_current_contract_wasm`. This PR wraps that capability in a secure, admin-controlled function to ensure only authorized upgrades, protecting user funds and protocol integrity.
+
+## Acceptance Criteria
+
+- [x] `upgrade` function exists and is admin-protected.
+- [x] Emits upgrade event.
+- [x] Storage compatibility is documented.
+- [x] Integration test proves code can be swapped while keeping escrow storage intact.
+- [x] Unauthorized users cannot trigger an upgrade.
+
+## Non-Goals
+
+- DAO-voting based upgrades (admin-only for now).
+
+---
+
+**Reviewer Notes:**  
+- Please review the storage compatibility comment for future upgrade safety.
+- All tests pass (`cargo test`).
+- No breaking changes to existing escrow logic.
+
+---