feat: Add profitability calculation schemas and service functions

- Introduced Pydantic schemas for profitability calculations in `schemas/calculations.py`.
- Implemented service functions for profitability calculations in `services/calculations.py`.
- Added new exception class `ProfitabilityValidationError` for handling validation errors.
- Created repositories for managing project and scenario profitability snapshots.
- Developed a utility script for verifying authenticated routes.
- Added a new HTML template for the profitability calculator interface.
- Implemented a script to fix user ID sequence in the database.

models/project.py

@@ -4,6 +4,7 @@ from datetime import datetime
 from typing import TYPE_CHECKING, List
 
 from .enums import MiningOperationType, sql_enum
+from .profitability_snapshot import ProjectProfitability
 
 from sqlalchemy import DateTime, ForeignKey, Integer, String, Text
 from sqlalchemy.orm import Mapped, mapped_column, relationship
@@ -51,6 +52,21 @@ class Project(Base):
         "PricingSettings",
         back_populates="projects",
     )
+    profitability_snapshots: Mapped[List["ProjectProfitability"]] = relationship(
+        "ProjectProfitability",
+        back_populates="project",
+        cascade="all, delete-orphan",
+        order_by=lambda: ProjectProfitability.calculated_at.desc(),
+        passive_deletes=True,
+    )
+
+    @property
+    def latest_profitability(self) -> "ProjectProfitability | None":
+        """Return the most recent profitability snapshot, if any."""
+
+        if not self.profitability_snapshots:
+            return None
+        return self.profitability_snapshots[0]
 
     def __repr__(self) -> str:  # pragma: no cover - helpful for debugging
         return f"Project(id={self.id!r}, name={self.name!r})"