feat: add ExerciseService with filtering and warmup support

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/services/exercise_service.py

@@ -0,0 +1,88 @@
+"""Service layer for exercise, warmup, and workout day data access.
+
+All exercise-related database operations go through this service.
+"""
+
+from typing import Optional
+
+import structlog
+from sqlmodel import Session, select
+
+from app.models.exercise import Exercise
+from app.models.warmup import Warmup
+from app.models.workout_day import WorkoutDay
+
+logger = structlog.get_logger(__name__)
+
+
+class ExerciseService:
+    """Handles read operations for exercises, warmups, and workout days.
+
+    Args:
+        session: An active SQLModel Session.
+    """
+
+    def __init__(self, session: Session) -> None:
+        self._session = session
+
+    def list_exercises(
+        self,
+        workout_day: Optional[str] = None,
+        muscle_group: Optional[str] = None,
+    ) -> list[Exercise]:
+        """List exercises with optional filtering.
+
+        Args:
+            workout_day: Filter by workout day name (e.g., "Push").
+            muscle_group: Filter by muscle group (e.g., "Chest").
+
+        Returns:
+            List of matching Exercise records.
+        """
+        statement = select(Exercise)
+        if workout_day:
+            statement = statement.where(Exercise.workout_day == workout_day)
+        if muscle_group:
+            statement = statement.where(Exercise.muscle_group == muscle_group)
+        return list(self._session.exec(statement).all())
+
+    def get_exercise_by_id(self, exercise_id: int) -> Optional[Exercise]:
+        """Retrieve an exercise by primary key.
+
+        Args:
+            exercise_id: The exercise ID.
+
+        Returns:
+            The Exercise record, or None if not found.
+        """
+        return self._session.get(Exercise, exercise_id)
+
+    def get_exercise_by_name(self, name: str) -> Optional[Exercise]:
+        """Retrieve an exercise by exact name match.
+
+        Args:
+            name: The exercise name to look up.
+
+        Returns:
+            The Exercise record, or None if not found.
+        """
+        statement = select(Exercise).where(Exercise.name == name)
+        return self._session.exec(statement).first()
+
+    def list_warmups(self) -> list[Warmup]:
+        """List all warmups in display order.
+
+        Returns:
+            List of Warmup records sorted by sort_order.
+        """
+        statement = select(Warmup).order_by(Warmup.sort_order)
+        return list(self._session.exec(statement).all())
+
+    def list_workout_days(self) -> list[WorkoutDay]:
+        """List all workout days in order.
+
+        Returns:
+            List of WorkoutDay records sorted by day_number.
+        """
+        statement = select(WorkoutDay).order_by(WorkoutDay.day_number)
+        return list(self._session.exec(statement).all())