fix(arrow-cast): respect cast safety for overflowing temporal casts

[SAY-5]

Which issue does this PR close?

• Part of temporal cast overflows/panics #10131.

Rationale for this change

Two temporal cast paths ignore the cast safety option:

• Time32(Second) to Time32(Millisecond) multiplies an i32 by 1000 with unary, so a large value panics with "attempt to multiply with overflow" in debug and wraps in release.
• Date64 to Date32 divides by MILLISECONDS_IN_DAY and then does an unchecked as i32, which silently truncates day counts that do not fit in i32 (e.g. i64::MAX produces -622191233).

Both are reachable from cast/cast_with_options on valid input and do not honour CastOptions::safe.

What changes are included in this PR?

Both casts now follow the same pattern already used elsewhere in this file (for decimal and timestamp casts): in safe mode out-of-range values become null via unary_opt with a checked operation, and in non-safe mode they return a CastError/ArithmeticOverflow via try_unary.

This covers the two cases shown in the issue. Other temporal casts that multiply into i64 (e.g. Time32(Second) to Time64) cannot overflow for in-range inputs and are left unchanged.

Are these changes tested?

Yes. Added test_cast_date64_to_date32_overflow and test_cast_time32_second_to_time32_millisecond_overflow, each checking that the safe cast nulls the out-of-range value and the non-safe cast errors instead of panicking or truncating. The existing temporal cast tests still pass.

Are there any user-facing changes?

These two casts no longer panic or silently truncate on overflow. Safe casts now yield null and non-safe casts return an error for the affected inputs.