feat(alerts): V17 migration — drop ACKNOWLEDGED, add read_at + deleted_at

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

cameleer-server-app/src/test/java/com/cameleer/server/app/alerting/storage/V17MigrationIT.java

@@ -0,0 +1,48 @@
+package com.cameleer.server.app.alerting.storage;
+
+import com.cameleer.server.app.AbstractPostgresIT;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class V17MigrationIT extends AbstractPostgresIT {
+
+    @Test
+    void alert_state_enum_drops_acknowledged() {
+        var values = jdbcTemplate.queryForList("""
+            SELECT unnest(enum_range(NULL::alert_state_enum))::text AS v
+            """, String.class);
+        assertThat(values).containsExactlyInAnyOrder("PENDING", "FIRING", "RESOLVED");
+    }
+
+    @Test
+    void read_at_and_deleted_at_columns_exist() {
+        var cols = jdbcTemplate.queryForList("""
+            SELECT column_name FROM information_schema.columns
+             WHERE table_name = 'alert_instances'
+               AND column_name IN ('read_at','deleted_at')
+            """, String.class);
+        assertThat(cols).containsExactlyInAnyOrder("read_at", "deleted_at");
+    }
+
+    @Test
+    void alert_reads_table_is_gone() {
+        Integer count = jdbcTemplate.queryForObject("""
+            SELECT COUNT(*)::int FROM information_schema.tables
+             WHERE table_name = 'alert_reads'
+            """, Integer.class);
+        assertThat(count).isZero();
+    }
+
+    @Test
+    void open_rule_index_predicate_is_reworked() {
+        String def = jdbcTemplate.queryForObject("""
+            SELECT pg_get_indexdef(indexrelid)
+              FROM pg_index
+              JOIN pg_class ON pg_class.oid = pg_index.indexrelid
+             WHERE pg_class.relname = 'alert_instances_open_rule_uq'
+            """, String.class);
+        assertThat(def).contains("state = ANY (ARRAY['PENDING'::alert_state_enum, 'FIRING'::alert_state_enum])");
+        assertThat(def).contains("deleted_at IS NULL");
+    }
+}