perf: resolve aliased field once during metadata inference

[osipovartem]

Which issue does this PR close?

Related to #24264. This isolates the alias single-resolution optimization from the broader, closed #24316.

Rationale for this change

Deriving a field for nested aliases resolves each child twice: once through metadata() and once through to_field(). Since metadata() itself calls to_field(), the work grows exponentially with alias depth. This affects schema inference and planning; no row execution path changes.

What changes are included in this PR?

Resolve the aliased child field once and read its metadata from that same field before applying explicit alias metadata. A 12-level regression test records 4,096 source-field lookups before the change and one after it, while checking metadata override, preserved metadata, output name, type, and nullability.

What is the testing strategy for this PR?

• cargo fmt --all --check
• cargo clippy --all-targets --all-features -- -D warnings
• cargo test -p datafusion-expr --lib (282 passed)
• Full documented extended workspace command with initialized test-data submodules and Arrow/Parquet fixtures (passed)
• Independent read-only review: approved with no blocking findings.

Are there any user-facing changes?

No schema or API behavior change; this reduces planning cost.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 86.11111% with 5 lines in your changes missing coverage. Please review.
✅ Project coverage is 82.77%. Comparing base (06aa131) to head (982f93b).

Files with missing lines	Patch %	Lines
datafusion/expr/src/expr_schema.rs	86.11%	4 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #26156      +/-   ##
==========================================
- Coverage   82.77%   82.77%   -0.01%     
==========================================
  Files        1147     1147              
  Lines      450909   450940      +31     
  Branches   450909   450940      +31     
==========================================
+ Hits       373252   373267      +15     
- Misses      54934    54946      +12     
- Partials    22723    22727       +4     

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