Checkpoint timing is currently measured in only a few WiredTiger code paths, which isn’t enough to diagnose checkpoint-related latency. We need better observability across the full checkpoint workflow.

Improvement:

• Add __checkpoint_verbose_track in more checkpoint phases/steps to increase timing coverage and make it easier to pinpoint where checkpoint time is spent.
• Add more states where applicable to increase granularity

Definition of Done

• __checkpoint_verbose_track and states added in key checkpoint areas to provide broad/end-to-end coverage.
• For new verbose messages, the output includes clear labels and is only emitted when checkpoint verbosity is enabled.
• No functional behavior change beyond added instrumentation.