Feature: Parzellenspezifische Kostenpositionsenzuweisung

- Neue Tabelle wp_kgvvm_parcel_cost_assignments für 1:N Zuordnungen
- CostRepository erweitert: get_assigned_entry_ids(), get_entry_ids_with_assignments(), assign_to_parcel(), unassign_from_parcel(), delete_assignments_for_entry()
- Admin: Neue POST-Action toggle_parcel_cost_assignment() mit Nonce-Sicherung
- Jahresabrechnung Parzelle: Rechte Seitenleiste zeigt alle Kostenpositions mit Zuordnungsstatus (✓ zugeordnet, ✗ nicht zugeordnet, – alle Parzellen)
- Berechnung: Kostenposten mit Beschränkung werden nur berechnet wenn Parzelle zugeordnet ist
- DataTransfer.php: parcel_cost_assignments in table_keys integriert für Export/Import
- DELETE-Handler bereinigt Zuordnungen beim Löschen einer Kostenposition

includes/Repositories/CostRepository.php

@@ -310,4 +310,146 @@ class CostRepository extends AbstractRepository {
 
 		return (float) $total;
 	}
+
+	// -------------------------------------------------------------------------
+	// Parcel cost assignments
+	// -------------------------------------------------------------------------
+
+	/**
+	 * Get the parcel cost assignments table name.
+	 *
+	 * @return string
+	 */
+	private function assignment_table() {
+		return Schema::table( 'parcel_cost_assignments' );
+	}
+
+	/**
+	 * Get cost entry IDs assigned to a specific parcel.
+	 *
+	 * @param int $parcel_id Parcel ID.
+	 * @return int[]
+	 */
+	public function get_assigned_entry_ids( $parcel_id ) {
+		$parcel_id = absint( $parcel_id );
+		$table     = $this->assignment_table();
+
+		if ( $parcel_id < 1 || '' === $table ) {
+			return array();
+		}
+
+		$ids = $this->wpdb->get_col( $this->wpdb->prepare( "SELECT cost_entry_id FROM {$table} WHERE parcel_id = %d", $parcel_id ) ); // phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared
+
+		return array_map( 'intval', (array) $ids );
+	}
+
+	/**
+	 * Get all cost entry IDs that have at least one parcel assignment.
+	 *
+	 * @param int $year Optional – filter by entry year (0 = all years).
+	 * @return int[]
+	 */
+	public function get_entry_ids_with_assignments( $year = 0 ) {
+		$table = $this->assignment_table();
+
+		if ( '' === $table ) {
+			return array();
+		}
+
+		$year = absint( $year );
+
+		if ( $year > 0 ) {
+			$ids = $this->wpdb->get_col( $this->wpdb->prepare( // phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared
+				"SELECT DISTINCT a.cost_entry_id FROM {$table} a
+				 INNER JOIN {$this->table} e ON e.id = a.cost_entry_id
+				 WHERE e.entry_year = %d",
+				$year
+			) );
+		} else {
+			$ids = $this->wpdb->get_col( "SELECT DISTINCT cost_entry_id FROM {$table}" ); // phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared,WordPress.DB.DirectDatabaseQuery.DirectQuery
+		}
+
+		return array_map( 'intval', (array) $ids );
+	}
+
+	/**
+	 * Assign a cost entry to a parcel.
+	 *
+	 * @param int $parcel_id     Parcel ID.
+	 * @param int $cost_entry_id Cost entry ID.
+	 * @return bool
+	 */
+	public function assign_to_parcel( $parcel_id, $cost_entry_id ) {
+		$parcel_id     = absint( $parcel_id );
+		$cost_entry_id = absint( $cost_entry_id );
+		$table         = $this->assignment_table();
+
+		if ( $parcel_id < 1 || $cost_entry_id < 1 || '' === $table ) {
+			return false;
+		}
+
+		$exists = (int) $this->wpdb->get_var( $this->wpdb->prepare( // phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared
+			"SELECT COUNT(*) FROM {$table} WHERE parcel_id = %d AND cost_entry_id = %d",
+			$parcel_id,
+			$cost_entry_id
+		) );
+
+		if ( $exists > 0 ) {
+			return true;
+		}
+
+		$result = $this->wpdb->insert(
+			$table,
+			array(
+				'parcel_id'     => $parcel_id,
+				'cost_entry_id' => $cost_entry_id,
+				'created_at'    => $this->now(),
+			),
+			array( '%d', '%d', '%s' )
+		);
+
+		return false !== $result;
+	}
+
+	/**
+	 * Remove a cost entry assignment from a parcel.
+	 *
+	 * @param int $parcel_id     Parcel ID.
+	 * @param int $cost_entry_id Cost entry ID.
+	 * @return bool
+	 */
+	public function unassign_from_parcel( $parcel_id, $cost_entry_id ) {
+		$parcel_id     = absint( $parcel_id );
+		$cost_entry_id = absint( $cost_entry_id );
+		$table         = $this->assignment_table();
+
+		if ( $parcel_id < 1 || $cost_entry_id < 1 || '' === $table ) {
+			return false;
+		}
+
+		$result = $this->wpdb->delete(
+			$table,
+			array(
+				'parcel_id'     => $parcel_id,
+				'cost_entry_id' => $cost_entry_id,
+			),
+			array( '%d', '%d' )
+		);
+
+		return false !== $result;
+	}
+
+	/**
+	 * Remove all parcel assignments for a cost entry (e.g. when the entry is deleted).
+	 *
+	 * @param int $cost_entry_id Cost entry ID.
+	 * @return void
+	 */
+	public function delete_assignments_for_entry( $cost_entry_id ) {
+		$table = $this->assignment_table();
+
+		if ( '' !== $table && absint( $cost_entry_id ) > 0 ) {
+			$this->wpdb->delete( $table, array( 'cost_entry_id' => absint( $cost_entry_id ) ), array( '%d' ) );
+		}
+	}
 }