feat: initialize project backend structure and document system specifications across all modules

docs/specs/customer_management/adjustment.md

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+---
+title: "Adjustment"
+type: OpenSpec
+status: Draft
+domain: Customer Management
+---
+
+# Adjustment
+
+## Requirement Definition
+Allows manual posting of adjustment transactions to correct balance discrepancies.
+
+## Process Flow
+
+### Pre-Conditions
+- Users must have access rights in the "Adjustment Entry" module.
+- Records require Maker-Checker approval.
+
+## Business Rules
+
+### Data Schema
+
+| Field Name | Description | Logic Type | Constraints / Rules |
+|---|---|---|---|
+| Posted Transaction By | Card, Account, or CIF. | Enum | Required. |
+| Card / Account / CIF | Identifier based on above selection. | String | Required. |
+| Adjustment Quantity Sign | Positive or Negative adjustment. | Enum | Required. |
+| Store | Store of transaction. | Enum (Lookup) | Required. |
+| Pool Id | Pool to be adjusted. | Enum (Lookup) | Required. Must respect entity level logic. |
+| Transaction Date | Transaction date time. | Date | Required. |
+| Expiry Date (Positive) | Expiry date of the new bucket. | Date | Required if Positive Adjustment. Defaults to pool policy. |
+| Bucket Expiry Date (Negative)| Specific bucket to deduct from. | Enum (Lookup) | Optional. If empty, uses FIFO Redemption approach. |
+| Adjustment Quantity | Amount to adjust. | Decimal | Required. Must be > 0. |
+| Reason Code | Reason for adjustment. | Enum (Lookup) | Required. |
+| Transaction Code | OLS transaction code. | Enum (Lookup) | Required. |
+| Remarks | Additional notes. | String (100) | Optional. |
+
+### Execution
+- **Pending/Approve Flow**: New adjustments go to a Pending state. Authorized user must approve.
+- **Positive Adjustments**: 
+  - Offsets any negative balance buckets first.
+  - Remaining points added to a new bucket with specified Expiry Date.
+- **Negative Adjustments**: 
+  - If a specific Bucket Expiry Date is chosen, deduction happens there.
+  - Otherwise, points are deducted based on FIFO.
+- OLS validates status, permissions, and block codes for the entity.
+
+## Post-Conditions
+- Pool balance buckets updated.
+- Transaction logged in history.
+
+## Exception Flow
+- Validation failures or insufficient permissions.