feat(profile): add profile settings and LLM user context

backend/alembic/versions/1f7e3b9c4a2d_add_user_profile_table.py

@@ -0,0 +1,45 @@
+"""add_user_profile_table
+
+Revision ID: 1f7e3b9c4a2d
+Revises: 8e4c1b7a9d2f
+Create Date: 2026-03-05 00:00:00.000000
+
+"""
+
+from typing import Sequence, Union
+
+import sqlalchemy as sa
+
+from alembic import op
+
+revision: str = "1f7e3b9c4a2d"
+down_revision: Union[str, None] = "8e4c1b7a9d2f"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.create_table(
+        "user_profiles",
+        sa.Column("id", sa.Uuid(), nullable=False),
+        sa.Column("birth_date", sa.Date(), nullable=True),
+        sa.Column("sex_at_birth", sa.String(length=16), nullable=True),
+        sa.Column("created_at", sa.DateTime(timezone=True), nullable=False),
+        sa.Column("updated_at", sa.DateTime(timezone=True), nullable=False),
+        sa.CheckConstraint(
+            "sex_at_birth IN ('male', 'female', 'intersex')",
+            name="ck_user_profiles_sex_at_birth",
+        ),
+        sa.PrimaryKeyConstraint("id"),
+    )
+    op.create_index(
+        op.f("ix_user_profiles_sex_at_birth"),
+        "user_profiles",
+        ["sex_at_birth"],
+        unique=False,
+    )
+
+
+def downgrade() -> None:
+    op.drop_index(op.f("ix_user_profiles_sex_at_birth"), table_name="user_profiles")
+    op.drop_table("user_profiles")