feat: Implement initial capex calculation feature

- Added CapexComponentInput, CapexParameters, CapexCalculationRequest, CapexCalculationResult, and related schemas for capex calculations.
- Introduced calculate_initial_capex function to aggregate capex components and compute totals and timelines.
- Created ProjectCapexRepository and ScenarioCapexRepository for managing capex snapshots in the database.
- Developed capex.html template for capturing and displaying initial capex data.
- Registered common Jinja2 filters for formatting currency and percentages.
- Implemented unit and integration tests for capex calculation functionality.
- Updated unit of work to include new repositories for capex management.

models/project.py

@@ -5,6 +5,7 @@ from typing import TYPE_CHECKING, List
 
 from .enums import MiningOperationType, sql_enum
 from .profitability_snapshot import ProjectProfitability
+from .capex_snapshot import ProjectCapexSnapshot
 
 from sqlalchemy import DateTime, ForeignKey, Integer, String, Text
 from sqlalchemy.orm import Mapped, mapped_column, relationship
@@ -59,6 +60,13 @@ class Project(Base):
         order_by=lambda: ProjectProfitability.calculated_at.desc(),
         passive_deletes=True,
     )
+    capex_snapshots: Mapped[List["ProjectCapexSnapshot"]] = relationship(
+        "ProjectCapexSnapshot",
+        back_populates="project",
+        cascade="all, delete-orphan",
+        order_by=lambda: ProjectCapexSnapshot.calculated_at.desc(),
+        passive_deletes=True,
+    )
 
     @property
     def latest_profitability(self) -> "ProjectProfitability | None":
@@ -68,5 +76,13 @@ class Project(Base):
             return None
         return self.profitability_snapshots[0]
 
+    @property
+    def latest_capex(self) -> "ProjectCapexSnapshot | None":
+        """Return the most recent capex snapshot, if any."""
+
+        if not self.capex_snapshots:
+            return None
+        return self.capex_snapshots[0]
+
     def __repr__(self) -> str:  # pragma: no cover - helpful for debugging
         return f"Project(id={self.id!r}, name={self.name!r})"