Restrict BOOL columns to boolean values

[agusaldasoro]

Problem

A boolean column is encoded as an SMT String, and SmtLibGenerator.appendBooleanConstraints restricts it to "true" or "false". That restriction was only applied when the declared type was exactly BOOLEAN. TYPE_MAP also accepts BOOL, which is how PostgreSQL reports a boolean column, and SMTLibZ3DbConstraintSolver already treats it as boolean when rebuilding genes (BOOLEAN_SPELLINGS).

A bool column therefore had no domain, and Z3 could give it any string. For WHERE active <> false, Z3 picks "". toBoolean("") reads that back as false, so the generated row violates the very query it was generated for.

Fix

• SmtLibGenerator.BOOLEAN_TYPES (BOOLEAN, BOOL) is the single set of boolean spellings.
• appendBooleanConstraints uses it, so a bool column gets the same domain as a BOOLEAN one.
• SMTLibZ3DbConstraintSolver.BOOLEAN_SPELLINGS now refers to the same set instead of repeating it, so the domain constraint and the gene reconstruction cannot drift apart again.

Tests

New BooleanColumnSolvingTest.boolSpellingIsRestrictedToBooleanValues, end to end against Z3. It uses the same H2 table with the column type set to "bool" and solves WHERE active <> false and WHERE active <> true. On master, the first case fails with expected: <true> but was: <false>. The second one only passes on master because "" happens to read back as false.

All tests under org.evomaster.core.database.sql.solver pass.