recsplit: support progress reporting

[AskAlexSharov]

from

[INFO] [02-28|06:26:16.790] [snapshots] Indexing                     progress="v1.1-commitment.2304-2560.vi=100%" total-indexing-time=12m0s alloc=4.3GB sys=11.2GB
[INFO] [02-28|06:26:36.790] [snapshots] Indexing                     progress="v1.1-commitment.2304-2560.vi=100%" total-indexing-time=12m20s alloc=4.5GB sys=11.2GB
[INFO] [02-28|06:26:56.790] [snapshots] Indexing                     progress="v1.1-commitment.2304-2560.vi=100%" total-indexing-time=12m40s alloc=4.7GB sys=11.2GB
[INFO] [02-28|06:27:16.790] [snapshots] Indexing                     progress="v1.1-commitment.2304-2560.vi=100%" total-indexing-time=13m0s alloc=4.5GB sys=11.2GB
[INFO] [02-28|06:27:36.791] [snapshots] Indexing                     progress="v1.1-commitment.2304-2560.vi=100%" total-indexing-time=13m20s alloc=4.3GB sys=11.2GB
[INFO] [02-28|06:27:56.790] [snapshots] Indexing                     progress="v1.1-commitment.2304-2560.vi=100%" total-indexing-time=13m40s alloc=7.8GB sys=11.2GB

to

INFO[03-01|03:40:03.227] [snapshots] Indexing                     progress="v2.0-storage.2304-2560.efi=40%, v1.1-storage.2304-2560.vi=6%" total-indexing-time=20s alloc=3.7GB sys=3.9GB
INFO[03-01|03:40:23.227] [snapshots] Indexing                     progress="v2.0-storage.2304-2560.efi=64%, v1.1-storage.2304-2560.vi=15%" total-indexing-time=40s alloc=3.8GB sys=4.0GB
INFO[03-01|03:40:43.227] [snapshots] Indexing                     progress="v2.0-storage.2304-2560.efi=83%, v1.1-storage.2304-2560.vi=23%" total-indexing-time=1m0s alloc=3.9GB sys=4.0GB
INFO[03-01|03:41:03.227] [snapshots] Indexing                     progress="v2.0-storage.2304-2560.efi=99%, v1.1-storage.2304-2560.vi=32%" total-indexing-time=1m20s alloc=5.0GB sys=5.2GB
INFO[03-01|03:41:23.227] [snapshots] Indexing                     progress="v1.1-storage.2304-2560.vi=41%" total-indexing-time=1m40s alloc=5.1GB sys=5.2GB
INFO[03-01|03:41:43.227] [snapshots] Indexing                     progress="v1.1-storage.2304-2560.vi=50%" total-indexing-time=2m0s alloc=3.6GB sys=5.4GB
INFO[03-01|03:42:03.227] [snapshots] Indexing                     progress="v1.1-storage.2304-2560.vi=53%" total-indexing-time=2m20s alloc=3.6GB sys=5.4GB
INFO[03-01|03:42:23.227] [snapshots] Indexing                     progress="v1.1-storage.2304-2560.vi=56%" total-indexing-time=2m40s alloc=3.6GB sys=5.4GB
INFO[03-01|03:42:43.226] [snapshots] Indexing                     progress="v1.1-storage.2304-2560.vi=60%" total-indexing-time=3m0s alloc=3.6GB sys=5.4GB
INFO[03-01|03:43:03.227] [snapshots] Indexing                     progress="v1.1-storage.2304-2560.vi=63%" total-indexing-time=3m20s alloc=3.6GB sys=5.4GB
INFO[03-01|03:43:23.227] [snapshots] Indexing                     progress="v1.1-storage.2304-2560.vi=67%" total-indexing-time=3m40s alloc=3.7GB sys=5.4GB
INFO[03-01|03:43:43.227] [snapshots] Indexing                     progress="v1.1-storage.2304-2560.vi=70%" total-indexing-time=4m0s alloc=3.7GB sys=5.4GB
INFO[03-01|03:44:03.227] [snapshots] Indexing                     progress="v1.1-storage.2304-2560.vi=74%" total-indexing-time=4m20s alloc=3.6GB sys=5.4GB
INFO[03-01|03:44:23.226] [snapshots] Indexing                     progress="v1.1-storage.2304-2560.vi=77%" total-indexing-time=4m40s alloc=3.6GB sys=5.4GB
INFO[03-01|03:44:43.227] [snapshots] Indexing                     progress="v1.1-storage.2304-2560.vi=80%" total-indexing-time=5m0s alloc=3.6GB sys=5.4GB

[Giulio2002]

LGTM — clean refactor centralizing progress tracking into RecSplit.SetProgress(), removing scattered duplicate progress code across call sites.