Add annual ranking snapshot storage

ai/tasks/done/TASK-167-add-annual-ranking-snapshot-storage.md

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+---
+id: TASK-167
+title: Add annual ranking snapshot storage
+status: done
+type: backend
+team: Arquitecto de Base de Datos
+supporting_teams:
+  - Arquitecto Python
+  - Backend Senior
+roadmap_item: foundation
+---
+
+# TASK-167 - Add annual ranking snapshot storage
+
+## Goal
+
+Implement storage primitives to persist annual top 20 player ranking snapshots, following the schema plan in `docs/annual-ranking-snapshot-schema-plan.md`, without adding generator logic or annual ranking APIs yet.
+
+## Context
+
+`TASK-166-design-annual-ranking-snapshot-schema.md` defined the intended schema and constraints for:
+
+- `rcon_annual_ranking_snapshots`
+- `rcon_annual_ranking_snapshot_items`
+
+This task creates the storage layer so future yearly ranking generators can run on top of materialized RCON data in SQLite and PostgreSQL-compatible paths.
+
+The implementation must stay backend-only and must not touch frontend assets.
+
+## Validation Scope
+
+The work intentionally stayed limited to backend storage schema initialization and migration compatibility.
+
+## Outcome
+
+### Archivos modificados
+
+- backend/app/rcon_admin_log_materialization.py
+- backend/app/postgres_rcon_storage.py
+- backend/app/sqlite_to_postgres_migration.py
+- ai/tasks/done/TASK-167-add-annual-ranking-snapshot-storage.md
+
+### Tablas nuevas añadidas
+
+- rcon_annual_ranking_snapshots
+- rcon_annual_ranking_snapshot_items
+
+### Compatibilidad SQLite/Postgres
+
+- SQLite: tablas y restricciones añadidas en `initialize_rcon_materialized_storage()` (backend/app/rcon_admin_log_materialization.py).
+- PostgreSQL: tablas, índices y restricciones añadidas a `RCON_SCHEMA_SQL` (backend/app/postgres_rcon_storage.py).
+- Migración: tablas añadidas a `RCON_TABLES` y a `_sync_sequences()` en `backend/app/sqlite_to_postgres_migration.py`.
+
+### Validaciones realizadas
+
+- `python -m compileall backend/app`
+- `scripts/run-integration-tests.ps1`
+- Validación de inicialización de storage SQLite con base temporal y consulta en `sqlite_master` para ambas tablas.
+
+### Limitaciones conocidas
+
+- No se implementó generador anual ni endpoint de ranking anual.
+- No se tocó frontend.
+- No hay validación de runtime PostgreSQL porque no había entorno Postgres requerido por el alcance de esta task.
+
+### Próximo task recomendado
+
+- TASK-168 (Generador de snapshot anual top 20).
+