Add all Gen 1-9 games with colors to seed data

- Add 37 games from Gen 1-9 (Red/Blue through Scarlet/Violet)
- Add color field to Game model matching box art/branding
- Add migration for games.color column
- Update fetch_pokeapi.py to fetch all games and output colors
- Update seed loader to upsert game colors
- Update frontend Game type to include color field

Games without PokeAPI encounter data (ORAS, Let's Go, Sword/Shield,
BDSP, Legends Arceus, Scarlet/Violet) have location structure but
empty encounter tables.

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

backend/src/app/alembic/versions/d4e5f6a7b8c9_add_game_color.py

@@ -0,0 +1,29 @@
+"""add color field to games
+
+Revision ID: d4e5f6a7b8c9
+Revises: c3d4e5f6a7b8
+Create Date: 2026-02-06 14:00:00.000000
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = 'd4e5f6a7b8c9'
+down_revision: Union[str, Sequence[str], None] = 'c3d4e5f6a7b8'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.add_column(
+        'games',
+        sa.Column('color', sa.String(7), nullable=True),
+    )
+
+
+def downgrade() -> None:
+    op.drop_column('games', 'color')