feat(dbquery): dialect-aware auto-quoting of simple identifiers in condition and field positions - #8

…ndition and field positions

Simple identifiers (ident / alias.ident) in WHERE/HAVING/ORDER BY/
GROUP BY/SELECT lists and UPDATE/DELETE conditions are now quoted per
dialect (backtick for MySQL/MariaDB/SQLite, double quotes for
Postgres), matching the existing INSERT/SET quoting. Raw expressions,
*, pre-quoted strings, Expression::raw() and niladic SQL literals
(NULL, TRUE, FALSE, DEFAULT, CURRENT_* et al.) stay untouched.
Fixes generated Postgres queries against camelCase columns
(SQLSTATE 42703; found by the Jardis Builder concurrency probe).
2268 tests green incl. camelCase matrix on three drivers and
Postgres INSERT->WHERE roundtrip with quoted DDL.