Expose paimon table observability API (snapshots, partitions, tags) for pypaimon_rust

[SML0127]

Search before asking

• I searched in the issues and found nothing similar.

Motivation

Beyond catalog metadata (issue #284), pypaimon_rust also lacks table-level introspection APIs that pypaimon exposes today: snapshot history, partition layout, and tags are not accessible from Python.

Solution

Add the following APIs to PyTable and introduce new wrapper classes:

# PyTable (additions)
table.latest_snapshot()  -> PySnapshot | None
table.list_snapshots()   -> list[PySnapshot]   # full history, newest first

# PySnapshot (new)
snapshot.id()                  -> int
snapshot.commit_time_ms()      -> int         # Snapshot::time_millis(), epoch ms
snapshot.total_record_count()  -> int | None  # None if not tracked
snapshot.delta_record_count()  -> int | None  # None if not tracked
snapshot.commit_kind()         -> str         # "APPEND" | "COMPACT" | "OVERWRITE" | "ANALYZE"

# PyTable (additions)
table.list_partitions()  -> list[dict[str, str]]
# e.g. [{"dt": "2024-01-01", "hr": "10"}, ...]

table.partition_stats()  -> list[PyPartitionStat]

# PyPartitionStat (new)
stat.partition()         -> dict[str, str]
stat.record_count()      -> int
stat.file_count()        -> int
stat.total_size_bytes()  -> int

# PyTable (addition)
table.list_tags() -> list[PyTag]

# PyTag (new)
tag.name()        -> str
tag.snapshot_id() -> int

Intended usage:

table = catalog.get_table("mydb.orders")
snap = table.latest_snapshot()

if snap:
    print(snap.commit_time_ms(), snap.total_record_count(), snap.commit_kind())

for stat in table.partition_stats():
    print(stat.partition(), stat.record_count(), stat.total_size_bytes())

for tag in table.list_tags():
    print(tag.name(), tag.snapshot_id())

Anything else?

No response

Willingness to contribute

• I'm willing to submit a PR!