[RyoKusnadi]

Problem: On the DuckDB engine, rowid fails with unknown column "rowid" in a SELECT list, as p.rowid, in WHERE, and in ORDER BY. DuckDB accepts all of these.

How it happens: Any DuckDB query that uses rowid on a table from schema.sql hits it. The table has no declared rowid column, and the engine only knew declared columns.

Steps to reproduce: Use the schema and queries from the issue (SELECT rowid, id FROM plan, WHERE rowid = $1) with engine: duckdb, then run sqlc generate.

Expected: Code is generated, with rowid as a nullable BIGINT (what DESCRIBE reports).
Actual: unknown column "rowid".

Cause: convertCreateTableInfo in internal/engine/duckdb/convert.go only emitted the declared columns. SQLite's fts5 hidden columns already use ColumnDef.IsHidden for "resolves by name, not in * or models". The DuckDB side never used it.

Fix: Add a hidden nullable bigint rowid column to every CREATE TABLE. Star expansion and the generated model stay the same. If the table declares its own rowid column, that one wins and nothing is added.

Scope: CREATE TABLE ... AS and views get no rowid. I haven't checked whether DuckDB exposes it for them. I did not touch #4677 (table alias as a value) or #4659 (table functions).

Testing: New case internal/endtoend/testdata/duckdb_rowid (select, qualified, WHERE, ORDER BY, SELECT * skips rowid, user-declared rowid). It needs no database. Before the fix it fails with the four errors from the issue. After: go test -C internal/endtoend -run 'TestReplay/base' . passes. go vet and gofmt are clean on the duckdb package. I did not run the full suite or the tests that need PostgreSQL/MySQL or a live DuckDB.

Environment: fix/duckdb-rowid-column @ 5d94812, go1.27.1, darwin/arm64.

Fixes #4676