fix(gcp/cloudsql): commitment price unit mismatch in getSQLPricing #1078

Problem

getSQLPricing in providers/gcp/services/cloudsql/client.go has the same per-unit vs term-total mismatch that was fixed for Memorystore and Cloud Storage in PR #1047.

The extractSQLPricingFromSKUs / extractSQLPriceFromSKU functions return a raw per-hour SKU price, but the code passes it directly to calculateSQLSavingsPercentage(onDemandPrice, hoursInTerm, commitmentPrice) which compares it against the term total onDemandPrice * hoursInTerm. This produces a savings percentage close to 100% instead of a realistic ~30%.

Additionally, HourlyRate = commitmentPrice / hoursInTerm divides an already-per-hour price by hours, yielding a near-zero rate.

Affected block (lines ~347-356):

hoursInTerm := 8760.0 * float64(termYears)
savingsPercentage := calculateSQLSavingsPercentage(onDemandPrice, hoursInTerm, commitmentPrice)

return &SQLPricing{
    HourlyRate:      commitmentPrice / hoursInTerm, // wrong: per-hour / hours
    CommitmentPrice: commitmentPrice,               // wrong: per-hour, not term total
    OnDemandPrice:   onDemandPrice * hoursInTerm,   // correct: term total
    ...
}

Fix

Mirror the fix applied to Memorystore and Cloud Storage in PR #1047:

commitmentPriceTerm := commitmentPrice * hoursInTerm
savingsPercentage := calculateSQLSavingsPercentage(onDemandPrice, hoursInTerm, commitmentPriceTerm)

return &SQLPricing{
    HourlyRate:      commitmentPrice,        // per-hour rate
    CommitmentPrice: commitmentPriceTerm,    // term total
    OnDemandPrice:   onDemandPrice * hoursInTerm,
    ...
}

Include a regression test that fails pre-fix (SavingsPercentage is ~99.99%) and passes after.

Context

Identified during PR #1047 CR review. The Memorystore and Cloud Storage variants were fixed in #1047. CloudSQL was not flagged by CR but has the identical issue.