SQL parser rejects negative numeric literals in `INSERT` statements

[rekhoff]

Originally reported by yuvalz1950 in the community Discord: SpacetimeDB's SQL parser treats negative numbers as unsupported expressions in INSERT VALUES clauses, causing "Unsupported INSERT value" errors for negative numeric data.

Problem:

INSERT INTO table (col) VALUES (-100.0);
-- Error: Unsupported INSERT value: -100.0

Internally we have validated the issue occurs in C#, Rust and TypeScript modules, indicating this impacts all modules, and is likely caused by how the SQL Parser currently parses signed numbers.