[Epic] SQL engine (v2) — bugs & gaps

The new SQL engine (`sqlEngine/`, #1285) is the engine on `main`. This epic collects its bugs and gaps.

## Scope

**In:** planning, binding, expression compilation, and execution under `sqlEngine/` — including correctness, hangs, and security defects in that code.

**Out:** #1648 (`[Epic] Legacy SQL (alasql) engine — bugs & gaps`), which covers the legacy path. Note the split isn't "anything mentioning alasql": the new engine still uses `alasql.parse` as its **parser** (`sqlEngine/parser/parse.ts`), so a parse-level defect can belong to either epic depending on which engine surfaces it. Route by which engine executes the query, not by whether alasql appears in the stack.

## Why a separate epic

#1648 has 18 children and is scoped to the legacy engine's behavior, most of which the v2 engine either doesn't share or fixes by construction. Filing v2 defects there would mix "bugs in the thing we're replacing" with "bugs in the replacement", which are different decisions — the first can often be closed by the cutover, the second cannot.

_Created during backlog triage; the child issues keep their own priorities and milestones._

Review the sqlEngine/ directory and the child issues for a specific v2 defect or gap; start with sqlEngine/parser/parse.ts when parsing behavior is involved. Done means resolving a scoped issue in planning, binding, expression compilation, or execution under the new engine.

Written by the indexing model from the issue text.