Summary

• add a persistent Create table action to the object explorer for PostgreSQL and SQLite, including empty databases
• add a two-step table designer with schema, columns, constraints, safe defaults, generated SQL review, and single-execution creation
• centralize database type/default-expression policy in one catalog shared by the React frontend and Rust backend
• add dedicated preview/create Tauri commands and dialect-specific SQL builders with identifier, type, duplicate-column, composite-key, and default validation
• refresh schema metadata and open the new table after creation without retrying DDL
• add interaction and integration coverage for the complete workflow, error preservation, unsupported engines, SQL generation, and SQLite/PostgreSQL database behavior

Why

Creating a basic table currently requires leaving the object explorer and writing DDL manually. This adds a constrained UI workflow that keeps the exact generated SQL reviewable and prevents arbitrary default expressions or automatic replay after ambiguous database errors.

Validation

• bun run check — 52 tests, typecheck, ESLint, and production build pass
• cargo test --lib — 36 tests pass
• cargo test --test sqlite_integration_tests — 30 pass, 1 benchmark ignored
• cargo test --no-run — all Rust test targets compile
• targeted create-table Rust and SQLite integration tests pass

Environment notes

• the PostgreSQL integration test reaches the local server but its default postgres credentials are rejected
• the full Rust suite reaches ClickHouse integration tests, but no ClickHouse service is running locally
• cargo fmt --check reports two pre-existing formatting differences on origin/main in src/database/queries/mod.rs and tests/unified_commands_tests.rs; feature files are formatted