feat: add AI data validation, test data generator, index advisor, and snapshots

Four new killer features leveraging AI (Ollama) and PostgreSQL internals:

- Data Validation: describe quality rules in natural language, AI generates
  SQL to find violations, run with pass/fail results and sample violations
- Test Data Generator: right-click table to generate realistic FK-aware test
  data with AI, preview before inserting in a transaction
- Index Advisor: analyze pg_stat tables + AI recommendations for CREATE/DROP
  INDEX with one-click apply
- Data Snapshots: export selected tables to JSON (FK-ordered), restore from
  file with optional truncate in a transaction

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/types/index.ts

@@ -394,7 +394,7 @@ export interface CloneResult {
   connection_url: string;
 }
 
-export type TabType = "query" | "table" | "structure" | "roles" | "sessions" | "lookup" | "erd";
+export type TabType = "query" | "table" | "structure" | "roles" | "sessions" | "lookup" | "erd" | "validation" | "index-advisor" | "snapshots";
 
 export interface Tab {
   id: string;
@@ -409,3 +409,159 @@ export interface Tab {
   lookupColumn?: string;
   lookupValue?: string;
 }
+
+// --- Wave 1: Validation ---
+
+export type ValidationStatus = "pending" | "generating" | "running" | "passed" | "failed" | "error";
+
+export interface ValidationRule {
+  id: string;
+  description: string;
+  generated_sql: string;
+  status: ValidationStatus;
+  violation_count: number;
+  sample_violations: unknown[][];
+  violation_columns: string[];
+  error: string | null;
+}
+
+export interface ValidationReport {
+  rules: ValidationRule[];
+  total_rules: number;
+  passed: number;
+  failed: number;
+  errors: number;
+  execution_time_ms: number;
+}
+
+// --- Wave 2: Data Generator ---
+
+export interface GenerateDataParams {
+  connection_id: string;
+  schema: string;
+  table: string;
+  row_count: number;
+  include_related: boolean;
+  custom_instructions?: string;
+}
+
+export interface GeneratedDataPreview {
+  tables: GeneratedTableData[];
+  insert_order: string[];
+  total_rows: number;
+}
+
+export interface GeneratedTableData {
+  schema: string;
+  table: string;
+  columns: string[];
+  rows: unknown[][];
+  row_count: number;
+}
+
+export interface DataGenProgress {
+  gen_id: string;
+  stage: string;
+  percent: number;
+  message: string;
+  detail: string | null;
+}
+
+// --- Wave 3A: Index Advisor ---
+
+export interface TableStats {
+  schema: string;
+  table: string;
+  seq_scan: number;
+  idx_scan: number;
+  n_live_tup: number;
+  table_size: string;
+  index_size: string;
+}
+
+export interface IndexStatsInfo {
+  schema: string;
+  table: string;
+  index_name: string;
+  idx_scan: number;
+  index_size: string;
+  definition: string;
+}
+
+export interface SlowQuery {
+  query: string;
+  calls: number;
+  total_time_ms: number;
+  mean_time_ms: number;
+  rows: number;
+}
+
+export type IndexRecommendationType = "create_index" | "drop_index" | "replace_index";
+
+export interface IndexRecommendation {
+  id: string;
+  recommendation_type: IndexRecommendationType;
+  table_schema: string;
+  table_name: string;
+  index_name: string | null;
+  ddl: string;
+  rationale: string;
+  estimated_impact: string;
+  priority: string;
+}
+
+export interface IndexAdvisorReport {
+  table_stats: TableStats[];
+  index_stats: IndexStatsInfo[];
+  slow_queries: SlowQuery[];
+  recommendations: IndexRecommendation[];
+  has_pg_stat_statements: boolean;
+}
+
+// --- Wave 3B: Snapshots ---
+
+export interface SnapshotMetadata {
+  id: string;
+  name: string;
+  created_at: string;
+  connection_name: string;
+  database: string;
+  tables: SnapshotTableMeta[];
+  total_rows: number;
+  file_size_bytes: number;
+  version: number;
+}
+
+export interface SnapshotTableMeta {
+  schema: string;
+  table: string;
+  row_count: number;
+  columns: string[];
+  column_types: string[];
+}
+
+export interface SnapshotProgress {
+  snapshot_id: string;
+  stage: string;
+  percent: number;
+  message: string;
+  detail: string | null;
+}
+
+export interface CreateSnapshotParams {
+  connection_id: string;
+  tables: TableRef[];
+  name: string;
+  include_dependencies: boolean;
+}
+
+export interface TableRef {
+  schema: string;
+  table: string;
+}
+
+export interface RestoreSnapshotParams {
+  connection_id: string;
+  file_path: string;
+  truncate_before_restore: boolean;
+}