feat: dd-trace 5.0 to 6.0 - move experimental.appsec options

[mohab-sameh]

Summary

Move removed experimental.appsec.* aliases to top-level appsec.*, and map
experimental.appsec.standalone.enabled to apmTracingEnabled.

Detection Criteria

Find .init(...) options reached through a local dd-trace binding or direct
require("dd-trace") call containing experimental: { appsec: { ... } }.

Transformation Logic

Move safe AppSec fields to top-level appsec. If standalone.enabled is
present, create top-level apmTracingEnabled.

Before / After Example

tracer.init({
  experimental: {
    appsec: {
      enabled: true,
      standalone: { enabled: false }
    }
  }
});

tracer.init({
  appsec: {
    enabled: true
  },
  apmTracingEnabled: false
});

Notes / Edge Cases

Skip Remote Configuration-only options and existing top-level conflicts.