Map Mastra classifier_evaluation spans to gen_ai.decide #25252

Follow getsentry/sentry-conventions#696: gen_ai.evaluate is deprecated in favor of gen_ai.decide.

The Mastra exporter maps classifier_evaluation spans to op gen_ai.evaluate and gen_ai.operation.name: evaluate (#25031).

Target span

• Op: gen_ai.decide (was gen_ai.evaluate)
• gen_ai.operation.name: decide (was evaluate)
• Name: decide <model> if the span name comes from the operation name.
• No other change. gen_ai.input.messages / gen_ai.output.messages keep type: 'evaluation'.

Scope

• packages/server-utils/src/ai/mastra/constants.ts (classifier_evaluation mapping).
• Update the tests: unit test test/ai/lib/tracing/mastra-exporter.test.ts; node-integration-tests suite mastra; e2e app node-mastra (classifier.test.ts).