Add game data seeding from PokeAPI with level ranges

Seed the database with Pokemon game data for 5 games (FireRed, LeafGreen,
Emerald, HeartGold, SoulSilver) using pokebase. Includes Alembic migrations
for route unique constraints and encounter level ranges, a two-phase seed
system (offline fetch to JSON, then idempotent upserts), and Dockerfile
updates for the seed runner.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/src/app/alembic/versions/694df688fb02_add_unique_constraint_routes_game_name.py

@@ -0,0 +1,32 @@
+"""add unique constraint routes game name
+
+Revision ID: 694df688fb02
+Revises: 03e5f186a9d5
+Create Date: 2026-02-05 13:01:30.631978
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = '694df688fb02'
+down_revision: Union[str, Sequence[str], None] = '03e5f186a9d5'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    """Upgrade schema."""
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.create_unique_constraint('uq_routes_game_name', 'routes', ['game_id', 'name'])
+    # ### end Alembic commands ###
+
+
+def downgrade() -> None:
+    """Downgrade schema."""
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_constraint('uq_routes_game_name', 'routes', type_='unique')
+    # ### end Alembic commands ###

backend/src/app/alembic/versions/9afcbafe9888_add_level_range_to_route_encounters.py

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+"""add level range to route encounters
+
+Revision ID: 9afcbafe9888
+Revises: 694df688fb02
+Create Date: 2026-02-05 13:32:35.559499
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = '9afcbafe9888'
+down_revision: Union[str, Sequence[str], None] = '694df688fb02'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    """Upgrade schema."""
+    op.add_column('route_encounters', sa.Column('min_level', sa.SmallInteger(), nullable=False, server_default='0'))
+    op.add_column('route_encounters', sa.Column('max_level', sa.SmallInteger(), nullable=False, server_default='0'))
+    op.alter_column('route_encounters', 'min_level', server_default=None)
+    op.alter_column('route_encounters', 'max_level', server_default=None)
+
+
+def downgrade() -> None:
+    """Downgrade schema."""
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_column('route_encounters', 'max_level')
+    op.drop_column('route_encounters', 'min_level')
+    # ### end Alembic commands ###