Add POI and POIDistance data models with migration

Introduces PointOfInterest (per-user named locations with lat/lng) and
POIDistance (travel time/distance per listing+POI+mode triple) SQLModel
entities, plus an Alembic migration to create both tables with indexes
and a composite unique constraint.

alembic/versions/c5d6e7f8a9b0_add_poi_tables.py

@@ -0,0 +1,70 @@
+"""add poi tables
+
+Revision ID: c5d6e7f8a9b0
+Revises: b4c7d8e9f0a1
+Create Date: 2026-02-08 12:00:00.000000
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+import sqlmodel
+
+
+# revision identifiers, used by Alembic.
+revision: str = 'c5d6e7f8a9b0'
+down_revision: Union[str, None] = 'b4c7d8e9f0a1'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    """Create pointofinterest and poidistance tables."""
+    op.create_table('pointofinterest',
+        sa.Column('id', sa.Integer(), nullable=False),
+        sa.Column('user_id', sa.Integer(), nullable=False),
+        sa.Column('name', sqlmodel.sql.sqltypes.AutoString(), nullable=False),
+        sa.Column('address', sqlmodel.sql.sqltypes.AutoString(), nullable=False),
+        sa.Column('latitude', sa.Float(), nullable=False),
+        sa.Column('longitude', sa.Float(), nullable=False),
+        sa.Column('created_at', sa.DateTime(), nullable=True,
+                  server_default=sa.func.now()),
+        sa.ForeignKeyConstraint(['user_id'], ['user.id']),
+        sa.PrimaryKeyConstraint('id'),
+    )
+    op.create_index(op.f('ix_pointofinterest_user_id'),
+                    'pointofinterest', ['user_id'], unique=False)
+
+    op.create_table('poidistance',
+        sa.Column('id', sa.Integer(), nullable=False),
+        sa.Column('listing_id', sa.Integer(), nullable=False),
+        sa.Column('listing_type', sqlmodel.sql.sqltypes.AutoString(), nullable=False),
+        sa.Column('poi_id', sa.Integer(), nullable=False),
+        sa.Column('travel_mode', sqlmodel.sql.sqltypes.AutoString(), nullable=False),
+        sa.Column('duration_seconds', sa.Integer(), nullable=False),
+        sa.Column('distance_meters', sa.Integer(), nullable=False),
+        sa.Column('computed_at', sa.DateTime(), nullable=True,
+                  server_default=sa.func.now()),
+        sa.ForeignKeyConstraint(['poi_id'], ['pointofinterest.id']),
+        sa.PrimaryKeyConstraint('id'),
+        sa.UniqueConstraint('listing_id', 'listing_type', 'poi_id', 'travel_mode',
+                            name='uq_poi_distance_listing_poi_mode'),
+    )
+    op.create_index(op.f('ix_poidistance_listing_id'),
+                    'poidistance', ['listing_id'], unique=False)
+    op.create_index(op.f('ix_poidistance_listing_type'),
+                    'poidistance', ['listing_type'], unique=False)
+    op.create_index(op.f('ix_poidistance_poi_id'),
+                    'poidistance', ['poi_id'], unique=False)
+
+
+def downgrade() -> None:
+    """Drop poidistance and pointofinterest tables."""
+    op.drop_index(op.f('ix_poidistance_poi_id'), table_name='poidistance')
+    op.drop_index(op.f('ix_poidistance_listing_type'), table_name='poidistance')
+    op.drop_index(op.f('ix_poidistance_listing_id'), table_name='poidistance')
+    op.drop_table('poidistance')
+
+    op.drop_index(op.f('ix_pointofinterest_user_id'), table_name='pointofinterest')
+    op.drop_table('pointofinterest')

models/poi.py

@@ -0,0 +1,13 @@
+from datetime import datetime
+
+from sqlmodel import SQLModel, Field
+
+
+class PointOfInterest(SQLModel, table=True):
+    id: int | None = Field(default=None, primary_key=True)
+    user_id: int = Field(foreign_key="user.id", index=True)
+    name: str = Field(nullable=False)
+    address: str = Field(nullable=False)
+    latitude: float = Field(nullable=False)
+    longitude: float = Field(nullable=False)
+    created_at: datetime = Field(default_factory=datetime.utcnow)

models/poi_distance.py

@@ -0,0 +1,23 @@
+from datetime import datetime
+
+from sqlmodel import SQLModel, Field, UniqueConstraint
+
+from models.listing import ListingType
+
+
+class POIDistance(SQLModel, table=True):
+    __table_args__ = (
+        UniqueConstraint(
+            "listing_id", "listing_type", "poi_id", "travel_mode",
+            name="uq_poi_distance_listing_poi_mode",
+        ),
+    )
+
+    id: int | None = Field(default=None, primary_key=True)
+    listing_id: int = Field(index=True, nullable=False)
+    listing_type: ListingType = Field(index=True, nullable=False)
+    poi_id: int = Field(foreign_key="pointofinterest.id", index=True, nullable=False)
+    travel_mode: str = Field(nullable=False)  # WALK, BICYCLE, TRANSIT
+    duration_seconds: int = Field(nullable=False)
+    distance_meters: int = Field(nullable=False)
+    computed_at: datetime = Field(default_factory=datetime.utcnow)