Migriere Persistenz von SQLite zu PostgreSQL (postgresql.lan:5432/essens)

- Dockerfile: pdo_pgsql installieren
- migrations: Postgres-Dialekt (SERIAL, TIMESTAMP(0), TEXT)
- compose/.env(.dist): postgresql://DATABASE_URL (Passwort via .env.local)
- bin/migrate-sqlite-to-pg.sh: einmaliger Datenimport SQLite->PG

Dockerfile

@@ -8,7 +8,7 @@ RUN apt-get update \
     && apt-get install -y --no-install-recommends git unzip sqlite3 libicu-dev \
     && rm -rf /var/lib/apt/lists/*
 
-RUN docker-php-ext-install bcmath intl
+RUN docker-php-ext-install bcmath intl pdo_pgsql
 
 COPY --from=composer:2 /usr/bin/composer /usr/bin/composer