fix: coerce uuid.UUID and os.PathLike to str for VARCHAR/JSON fields

[pangwangshu]

Summary

Fixes #2917. Inserting a uuid.UUID or pathlib.Path value into a VARCHAR field — or nesting one inside a JSON/dynamic field — failed instead of auto-converting to a string, as the issue requested.

#3408 attempted this by patching dtype inference only. @XuanYang-cn correctly flagged that as incomplete (comment): convert_to_str_array/entity_to_str_arr reject non-str values independently of dtype inference. This PR fixes all three points on that path:

• orm/types.py — infer_dtype_by_scalar_data/infer_dtype_bydata recognize UUID/PathLike as VARCHAR (previously UNKNOWN; PathLike could also crash infer_dtype_bydata via an uncaught TypeError).
• client/entity_helper.py — convert_to_str_array coerces UUID→str / PathLike→os.fspath(), for both the row-insert (scalar) and column-insert (list) call paths.
• client/entity_helper.py — convert_to_json now handles PathLike nested in JSON/dynamic fields (previously a raw orjson TypeError).

Test plan

• Unit tests for dtype inference, convert_to_str_array (both call paths), and convert_to_json
• End-to-end tests via pack_field_value_to_field_data / entity_to_field_data — the real insert path, not just the helpers in isolation (the gap that made fix: infer uuid.UUID and os.PathLike as VARCHAR in dtype inference #3408 look sufficient)
• make coverage (full unit suite) — passing
• make integration-lite — passing
• make lint — clean

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[shashvat-singham]

Ran the branch. The VARCHAR side does what it says, and the tuple fix in the walker is a nice catch — (PurePosixPath("/a/b"),) really did stay unconverted before.

I went looking for a uuid.UUID branch in preprocess_numpy_types to match the os.PathLike one and couldn't find it, assumed that was an oversight, then tested it and found it works anyway — orjson serialises UUID natively, so the walker doesn't need to touch it. Worth noting in case a future reader has the same reaction I did.

That does leave one real gap, though: it works because orjson handles it, and orjson isn't always the serialiser. convert_to_json falls back to stdlib json past orjson's ~500-level recursion limit, and stdlib json has no native UUID support:

def nest(leaf, depth):
    o = leaf
    for _ in range(depth):
        o = {"n": o}
    return o

convert_to_json(nest(uuid.UUID(int=0), 10))    # b'{"n":...{"n":"00000000-..."}}'
convert_to_json(nest(uuid.UUID(int=0), 600))   # TypeError: Object of type UUID is not JSON serializable
convert_to_json(nest(PurePosixPath("/a/b"), 600))  # fine

PathLike survives the deep case precisely because this PR normalises it to str in the walker, before either serialiser sees it. UUID doesn't, so a JSON field nested past ~500 levels still raises the raw TypeError that GH-2917 is about.

To be clear this fails the same way on master, so it's not a regression from this PR — but since the PR's stated goal is making UUID and PathLike work in VARCHAR and JSON fields, and it fixes the deep case for one and not the other, it seems worth closing here. Adding

elif isinstance(current, uuid.UUID):
    assign_to_parent(str(current))

next to the PathLike branch would make both paths serialiser-independent and match the reasoning already in that comment block.

Admittedly 500-deep JSON is an unusual payload, so if you'd rather keep this PR tight I'm happy to send that as a follow-up — just flagging it while the context is fresh.

[pangwangshu]

@shashvat-singham Good catch, thanks for digging into the fallback path. Added an explicit uuid.UUID branch next to the PathLike one in preprocess_numpy_types so it's normalized to str before either serializer sees it, instead of relying on orjson's native support: 07cfff7

Verified with your exact repro — convert_to_json(nest(uuid.UUID(int=0), 600)) now succeeds instead of raising TypeError, and added a regression test covering the >500-level stdlib json fallback case.