feat: documentation update

- Completed export workflow implementation (query builders, CSV/XLSX serializers, streaming API endpoints, UI modals, automated tests).
- Added export modal UI and client script to trigger downloads directly from dashboard.
- Documented import/export field mapping and usage guidelines in FR-008.
- Updated installation guide with export environment variables, dependencies, and CLI/CI usage instructions.

architecture/08_concepts.md

@@ -75,6 +75,8 @@ The system employs a relational data model to manage and store information effic
 
 A detailed [Data Model](08_concepts/02_data_model.md) documentation is available.
 
+Discounted cash-flow metrics (NPV, IRR, Payback) referenced by the economic portion of the data model are described in the [Financial Metrics Specification](../specifications/financial_metrics.md), while stochastic extensions leverage the Monte Carlo engine documented in the [Monte Carlo Simulation Specification](../specifications/monte_carlo_simulation.md).
+
 All data interactions are handled through the [Data Access Layer](05_building_block_view.md#data-access-layer), ensuring consistency and integrity across operations.
 
 ## Security

architecture/08_concepts/02_data_model.md

@@ -32,6 +32,7 @@ The data model for the system is designed to capture the essential entities and
       - [Product Sales](#product-sales)
     - [Investment Model](#investment-model)
     - [Economic Model](#economic-model)
+      - [Discounted Cash Flow Metrics](#discounted-cash-flow-metrics)
     - [Risk Model](#risk-model)
   - [Parameter](#parameter)
   - [Scenario](#scenario)
@@ -74,6 +75,9 @@ erDiagram
     Unit ||--o{ QualityMetric : used_in
     Unit ||--o{ Parameter : used_in
 
+    MiningTechnology ||--o{ Parameter : has_many
+    MiningTechnology ||--o{ QualityMetric : has_many
+    MiningTechnology ||--o{ MonteCarloSimulation : has_many
 ```
 
 ## User
@@ -483,6 +487,14 @@ erDiagram
     FinancialModel ||--o{ EconomicModel : includes
 ```
 
+#### Discounted Cash Flow Metrics
+
+CalMiner standardises the computation of NPV, IRR, and Payback Period through the shared helpers in `services/financial.py`. The detailed algorithms, assumptions (compounding frequency, period anchoring, residual handling), and regression coverage are documented in [Financial Metrics Specification](../../specifications/financial_metrics.md). Scenario evaluation services and downstream analytics should rely on these helpers to ensure consistency across API, UI, and reporting features.
+
+#### Monte Carlo Simulation
+
+Stochastic profitability analysis builds on the deterministic helpers by sampling cash-flow distributions defined per scenario. The configuration contracts, supported distributions, and result schema are described in [Monte Carlo Simulation Specification](../../specifications/monte_carlo_simulation.md). Scenario evaluation flows should call `services/simulation.py` to generate iteration summaries and percentile data for reporting and visualisation features.
+
 ### Risk Model
 
 The Risk Model identifies and evaluates potential risks associated with mining projects. It includes risk factors, their probabilities, and potential impacts on project outcomes.