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/capex_snapshot.py

@@ -0,0 +1,111 @@
+from __future__ import annotations
+
+from datetime import datetime
+from typing import TYPE_CHECKING
+
+from sqlalchemy import JSON, DateTime, ForeignKey, Integer, Numeric, String
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+from sqlalchemy.sql import func
+
+from config.database import Base
+
+if TYPE_CHECKING:  # pragma: no cover
+    from .project import Project
+    from .scenario import Scenario
+    from .user import User
+
+
+class ProjectCapexSnapshot(Base):
+    """Snapshot of aggregated initial capex metrics at the project level."""
+
+    __tablename__ = "project_capex_snapshots"
+
+    id: Mapped[int] = mapped_column(Integer, primary_key=True)
+    project_id: Mapped[int] = mapped_column(
+        ForeignKey("projects.id", ondelete="CASCADE"), nullable=False, index=True
+    )
+    created_by_id: Mapped[int | None] = mapped_column(
+        ForeignKey("users.id", ondelete="SET NULL"), nullable=True, index=True
+    )
+    calculation_source: Mapped[str | None] = mapped_column(
+        String(64), nullable=True)
+    calculated_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), nullable=False, server_default=func.now()
+    )
+    currency_code: Mapped[str | None] = mapped_column(String(3), nullable=True)
+    total_capex: Mapped[float | None] = mapped_column(
+        Numeric(18, 2), nullable=True)
+    contingency_pct: Mapped[float | None] = mapped_column(
+        Numeric(12, 6), nullable=True)
+    contingency_amount: Mapped[float | None] = mapped_column(
+        Numeric(18, 2), nullable=True)
+    total_with_contingency: Mapped[float | None] = mapped_column(
+        Numeric(18, 2), nullable=True)
+    component_count: Mapped[int | None] = mapped_column(Integer, nullable=True)
+    payload: Mapped[dict | None] = mapped_column(JSON, nullable=True)
+    created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), nullable=False, server_default=func.now()
+    )
+    updated_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), nullable=False, server_default=func.now(), onupdate=func.now()
+    )
+
+    project: Mapped[Project] = relationship(
+        "Project", back_populates="capex_snapshots"
+    )
+    created_by: Mapped[User | None] = relationship("User")
+
+    def __repr__(self) -> str:  # pragma: no cover
+        return (
+            "ProjectCapexSnapshot(id={id!r}, project_id={project_id!r}, total_capex={total_capex!r})".format(
+                id=self.id, project_id=self.project_id, total_capex=self.total_capex
+            )
+        )
+
+
+class ScenarioCapexSnapshot(Base):
+    """Snapshot of initial capex metrics for an individual scenario."""
+
+    __tablename__ = "scenario_capex_snapshots"
+
+    id: Mapped[int] = mapped_column(Integer, primary_key=True)
+    scenario_id: Mapped[int] = mapped_column(
+        ForeignKey("scenarios.id", ondelete="CASCADE"), nullable=False, index=True
+    )
+    created_by_id: Mapped[int | None] = mapped_column(
+        ForeignKey("users.id", ondelete="SET NULL"), nullable=True, index=True
+    )
+    calculation_source: Mapped[str | None] = mapped_column(
+        String(64), nullable=True)
+    calculated_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), nullable=False, server_default=func.now()
+    )
+    currency_code: Mapped[str | None] = mapped_column(String(3), nullable=True)
+    total_capex: Mapped[float | None] = mapped_column(
+        Numeric(18, 2), nullable=True)
+    contingency_pct: Mapped[float | None] = mapped_column(
+        Numeric(12, 6), nullable=True)
+    contingency_amount: Mapped[float | None] = mapped_column(
+        Numeric(18, 2), nullable=True)
+    total_with_contingency: Mapped[float | None] = mapped_column(
+        Numeric(18, 2), nullable=True)
+    component_count: Mapped[int | None] = mapped_column(Integer, nullable=True)
+    payload: Mapped[dict | None] = mapped_column(JSON, nullable=True)
+    created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), nullable=False, server_default=func.now()
+    )
+    updated_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), nullable=False, server_default=func.now(), onupdate=func.now()
+    )
+
+    scenario: Mapped[Scenario] = relationship(
+        "Scenario", back_populates="capex_snapshots"
+    )
+    created_by: Mapped[User | None] = relationship("User")
+
+    def __repr__(self) -> str:  # pragma: no cover
+        return (
+            "ScenarioCapexSnapshot(id={id!r}, scenario_id={scenario_id!r}, total_capex={total_capex!r})".format(
+                id=self.id, scenario_id=self.scenario_id, total_capex=self.total_capex
+            )
+        )