Benchmark: 200 threads default, p99 latency chart (linear)

- Raise the default concurrent thread count to 200 (was 128) in the workflow
  input and env fallback and in the JMX __P default.
- Latency chart now plots p99 instead of mean: tail latency is the more
  meaningful metric for the skewed LDAP latency distributions under load (mean
  hides the tail). The Y axis is linear (logarithmic scale removed).