feat: add rejectionNotes field to Game and mobile admin listing schemas

[coderabbitai]

Rejection notes are referenced in code but the field does not yet exist in the Prisma schema.

Files with TODO comments:

• src/server/api/routers/games.ts lines 723–724 — rejectionNotes missing from Game schema
• src/server/api/routers/mobile/admin.ts line 358 — rejectionNotes field missing from listing schema

Action required:

• Add rejectionNotes String? (nullable) to the Game model and the mobile listing model in prisma/schema.prisma.
• Create a migration.
• Wire it up in the rejection mutation payloads.

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Requested by @Producdevity — related to PR #375