pgpool: Feature: Add Lifecheck Started status to pcp_watchdog_info outp

Feature: Add Lifecheck Started status to pcp_watchdog_info output.

This commit enhances the pcp_watchdog_info command by adding a new field,
Lifecheck Started, which indicates whether lifecheck has been started
on each watchdog node (NO: not started, YES: started).

This allows users to check the lifecheck status directly from the command
output without inspecting logs.

Add a lifecheck_started member to WatchdogNode. When the lifecheck process
detects that lifecheck has started, it notifies the watchdog process, which
sets lifecheck_started to true. When set to true, the status is propagated
across the cluster.

Add a lifecheck_status field to pcp_watchdog_info so that the latest
lifecheck_started status is displayed when the command is called.

Branch
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master

Details
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https://git.postgresql.org/gitweb?p=pgpool2.git;a=commitdiff;h=366e602bca9ecc70f91fb52afcad74facbcec215

Modified Files
--------------
doc.ja/src/sgml/ref/pcp_watchdog_info.sgml | 11 ++++++++---
doc/src/sgml/ref/pcp_watchdog_info.sgml | 10 +++++++---
src/include/pcp/pcp.h | 1 +
src/include/watchdog/watchdog.h | 2 ++
src/include/watchdog/wd_commands.h | 2 ++
src/include/watchdog/wd_ipc_defines.h | 2 +-
src/include/watchdog/wd_lifecheck.h | 3 ++-
src/libs/pcp/pcp.c | 6 ++++++
src/tools/pcp/pcp_frontend_client.c | 8 +++++---
src/watchdog/watchdog.c | 13 +++++++++++++
src/watchdog/wd_commands.c | 7 +++++++
src/watchdog/wd_json_data.c | 4 +++-
src/watchdog/wd_lifecheck.c | 10 +++++++++-
13 files changed, 66 insertions(+), 13 deletions(-)