Add per-condition encounter rates to seed data (#26)

Co-authored-by: Julian Tabel <juliantabel.jt@gmail.com>
Co-committed-by: Julian Tabel <juliantabel.jt@gmail.com>

backend/src/app/alembic/versions/h9c0d1e2f3a4_add_condition_to_route_encounters.py

@@ -0,0 +1,54 @@
+"""add condition to route encounters
+
+Revision ID: h9c0d1e2f3a4
+Revises: g8b9c0d1e2f3
+Create Date: 2026-02-17 12:00:00.000000
+
+"""
+
+from collections.abc import Sequence
+
+import sqlalchemy as sa
+from alembic import op
+
+# revision identifiers, used by Alembic.
+revision: str = "h9c0d1e2f3a4"
+down_revision: str | Sequence[str] | None = "g8b9c0d1e2f3"
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
+
+
+def upgrade() -> None:
+    op.add_column(
+        "route_encounters",
+        sa.Column(
+            "condition",
+            sa.String(30),
+            nullable=False,
+            server_default="",
+        ),
+    )
+    op.drop_constraint(
+        "uq_route_pokemon_method_game",
+        "route_encounters",
+        type_="unique",
+    )
+    op.create_unique_constraint(
+        "uq_route_pokemon_method_game_condition",
+        "route_encounters",
+        ["route_id", "pokemon_id", "encounter_method", "game_id", "condition"],
+    )
+
+
+def downgrade() -> None:
+    op.drop_constraint(
+        "uq_route_pokemon_method_game_condition",
+        "route_encounters",
+        type_="unique",
+    )
+    op.create_unique_constraint(
+        "uq_route_pokemon_method_game",
+        "route_encounters",
+        ["route_id", "pokemon_id", "encounter_method", "game_id"],
+    )
+    op.drop_column("route_encounters", "condition")