SQLAlchemy compliance: audit numeric range and float precision

[laughingman7743]

Context

Parent issue: #736

IntegerTest.test_huge_int remains skipped.
The precision_generic_float_type requirement is closed because REAL values do not satisfy SQLAlchemy precision expectations.

Scope

• Verify integer values outside the Athena BIGINT range and classify the result as a dialect gap or engine limitation.
• Verify SQLAlchemy generic Float mapping against Athena REAL and DOUBLE.
• Open precision requirements only when the declared SQLAlchemy type can satisfy them.
• Keep overflow and precision limitations explicit.

Acceptance criteria

• Supported numeric tests pass with the correct Python result types.
• Genuine BIGINT or REAL limits remain gated with confirmed reasons.
• Compiler and type mapping changes have focused regression tests.
• just lint passes.
• Athena tests are limited to the affected nodes and run with -n 1.