fix: coerce INT96 in two-level and legacy Parquet lists

[ranflarion]

Which issue does this PR close?

• Closes coerce_int96 leaves INT96 in two-level and legacy Parquet lists as nanoseconds #26463.

Rationale for this change

With coerce_int96 set, INT96 timestamps inside Hive's two-level lists (how Hive writes array<timestamp>), bare repeated int96 fields and parquet-mr Avro's array lists stay Timestamp(Nanosecond, None), so values outside 1677-2262 overflow on decode, which is what coerce_int96 exists to prevent.

What changes are included in this PR?

Int96Coercer no longer rebuilds Parquet paths from Arrow field names, which assumed the three-level <list>.list.<element> layout. For each top-level field it records which of its Parquet leaf columns are INT96, in the depth-first order in which arrow-rs maps them to Arrow leaves, and walks the field's Arrow type in that order, so the list or map encoding no longer matters. Top-level fields are still matched by name, so a projected file schema keeps working. The walk now also descends LargeList and FixedSizeList, and replaces the explicit stack with a short recursion that keeps field metadata via field_with_new_type.

What is the testing strategy for this PR?

coerce_int96_to_resolution_with_two_level_and_legacy_lists covers a Hive two-level list, a bare repeated field, an Avro-style array list of structs, a three-level list, a map value and a non-INT96 nanosecond timestamp, and then a projected, reordered file schema. It fails on main for the first three. The existing nested-type and field-metadata tests pass unchanged.

Are there any user-facing changes?

No API changes. INT96 columns in those list layouts now coerce like the rest.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 94.28571% with 8 lines in your changes missing coverage. Please review.
✅ Project coverage is 82.89%. Comparing base (290ad15) to head (d563395).

Files with missing lines	Patch %	Lines
...tafusion/datasource-parquet/src/schema_coercion.rs	94.28%	8 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #26464      +/-   ##
==========================================
- Coverage   82.89%   82.89%   -0.01%     
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  Files        1154     1154              
  Lines      457656   457678      +22     
  Branches   457656   457678      +22     
==========================================
+ Hits       379391   379398       +7     
- Misses      55261    55272      +11     
- Partials    23004    23008       +4     

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