ZOOKEEPER-5069: Add AdminServer command to query watch registration details

[hedong1123]

Motivation

The existing watches, watches_by_path, and watch_summary AdminServer
commands do not provide per-Watch details correlated with current client
connection information. This makes Watch registration diagnostics difficult.

Changes

• Add the read-only AdminServer command watch_details and the four-letter
  command alias wchd.
• Support exact path, session_id, and client_ip filters, plus a limit
  parameter with a default of 100 and a maximum of 1000.
• Return local Watch registrations only; results are not aggregated across the
  ZooKeeper ensemble.
• Return client connection details, including Session ID, client IP and port,
  connection establishment time, session timeout, and TLS state.
• Return watch_kind as an ordered array of event coverage:
  ["data"], ["children"], or ["data", "children"].
• Aggregate registrations by path + session_id + watch_mode, so Data and
  Children Watches for the same Standard Watch context are returned as one
  entry.
• Support Standard, Persistent, and Persistent Recursive Watch modes.
• Apply the result limit after aggregation and report truncation with
  returned_count and truncated.
• Preserve binary compatibility for third-party IWatchManager
  implementations through a default interface method.
• Do not add command-specific AdminServer authentication or ACL restrictions.

[hedong1123]

The Jenkins failure is unrelated to this PR. It is a timeout in
ZooKeeperServerClusterMutualAuthTest.testStart while waiting for Leader election.

The watch_details-related tests passed, and the failing test passed when rerun
individually with -Dsurefire-forkcount=4. Re-triggering the pre-commit check.