feat(go): add UseWasmInterpreter config for signal-safe WASM execution

[fabriziodemaria]

Summary

• Add UseWasmInterpreter to ProviderConfig and ProviderTestConfig so callers can opt into wazero interpreter mode instead of the default JIT compiler.
• When enabled, the runtime is created with wazero.NewRuntimeConfigInterpreter(), keeping WASM evaluation on normal Go goroutine stacks so SIGPROF/SIGURG can be handled safely on linux/arm64.
• Default behavior is unchanged (UseWasmInterpreter: false).

Motivation

temporal-worker pods on linux/arm64 under CPU profiling or goroutine preemption can exit silently (exit code 139, no Go traceback) when signals land during wazero JIT execution. Interpreter mode trades performance for signal safety.

Usage

provider, err := confidence.NewProvider(ctx, confidence.ProviderConfig{
    ClientSecret:       "...",
    EncryptionKey:      "...",
    UseWasmInterpreter: true,
})

Test plan

• go test ./confidence/internal/local_resolver/... -run InterpreterMode
• go build ./...
• Benchmark flag evaluation with and without interpreter mode on arm64
• Enable UseWasmInterpreter: true on temporal-worker staging and monitor crash rate + latency

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