feat(io): add ResolvingFileIO to resolve FileIO by location scheme and forward vended credentials

[plusplusjiajia]

Follow-up to #719: replaces the temporary warehouse-based FileIO detection
with a scheme-based ResolvingFileIO, mirroring Java.

Why

The FileIO impl was picked from DetectBuiltinFileIO(warehouse), so any
non-s3:// warehouse resolved to arrow-fs-local and binding vended
credentials failed with Configured FileIO does not support vended storage credentials. Credential-vending catalogs typically use a logical warehouse
identifier (bucket ARN / catalog name), not a storage URI, so the feature
only worked when warehouse was literally s3://….

What

1. ResolvingFileIO (core) — picks the impl per file-path scheme
   (s3/s3a/s3n/oss → arrow-fs-s3; file/no scheme → local; else
   NotSupported), lazily loaded via FileIORegistry and cached; forwards
   the full credential list to impls that support it (Java
   ResolvingFileIO semantics). Registered as resolving-file-io.
2. REST default — MakeCatalogFileIO defaults to resolving-file-io
   when io-impl is unset (Java DEFAULT_FILE_IO_IMPL likewise); the
   warehouse detection and the io-impl-vs-warehouse check are removed.
   Explicit io-impl is honored as before.
3. ArrowS3FileIO — SetStorageCredentials skips non-S3 credential
   prefixes instead of rejecting the set (Java S3FileIO filters by "s3");
   servers may vend credentials for several storage systems at once.

[MisterRaindrop]

Could we add an end-to-end test using the actual Arrow FileIO implementations? The current tests use mocks and don’t cover the full REST → ResolvingFileIO → FileIORegistry → Arrow FileIO path.

[Copilot]

Pull request overview

This PR introduces a core ResolvingFileIO that selects the concrete FileIO implementation based on each file path’s URI scheme (instead of inferring from warehouse), and updates the REST catalog defaults and S3 credential handling to match Iceberg Java semantics for vended credentials.

Changes:

• Add ResolvingFileIO (core) with per-scheme resolution, lazy loading via FileIORegistry, caching, and forwarding of vended storage credentials.
• Change REST catalog MakeCatalogFileIO default to resolving-file-io when io-impl is unset; remove warehouse-based auto-detection and compatibility checks.
• Update ArrowS3FileIO::SetStorageCredentials to skip (not reject) non-S3 credential prefixes and warn when none are S3-compatible; add/adjust tests accordingly.

Reviewed changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/iceberg/test/rest_file_io_test.cc	Updates REST FileIO tests for resolving default and logical-warehouse credential binding regression coverage.
src/iceberg/test/resolving_file_io_test.cc	Adds unit tests for scheme resolution, routing/caching behavior, and credential forwarding semantics.
src/iceberg/test/meson.build	Adds resolving_file_io_test.cc to Meson test sources.
src/iceberg/test/CMakeLists.txt	Adds resolving_file_io_test.cc to CMake test sources.
src/iceberg/test/arrow_s3_file_io_test.cc	Updates S3 FileIO credential-prefix behavior tests (skip non-S3; accept no-S3 case).
src/iceberg/resolving_file_io.h	Declares new ResolvingFileIO API and caching/credential-forwarding behavior.
src/iceberg/resolving_file_io.cc	Implements per-scheme resolution, lazy registry loading, caching, and credential forwarding.
src/iceberg/meson.build	Adds resolving_file_io.cc to core build sources and installs the new header.
src/iceberg/file_io_registry.h	Introduces the kResolvingFileIO registry name constant.
src/iceberg/file_io_registry.cc	Pre-registers resolving-file-io in the registry state constructor.
src/iceberg/CMakeLists.txt	Adds resolving_file_io.cc to core CMake sources.
src/iceberg/catalog/rest/rest_file_io.h	Removes builtin-detection declarations; documents resolving default behavior.
src/iceberg/catalog/rest/rest_file_io.cc	Defaults to resolving-file-io when io-impl is unset; simplifies table FileIO creation flow.
src/iceberg/arrow/s3/arrow_s3_file_io.cc	Skips non-S3 credential prefixes and logs a warning when all are skipped.

[plusplusjiajia]

Could we add an end-to-end test using the actual Arrow FileIO implementations? The current tests use mocks and don’t cover the full REST → ResolvingFileIO → FileIORegistry → Arrow FileIO path.

@MisterRaindrop Done in test/rest_arrow_file_io_test.cc — full REST -> ResolvingFileIO -> registry -> Arrow FileIO chain against the real implementations: a local round-trip with real bytes, plus an S3 case asserting a vended oss:// credential is applied. Good suggestion — the mocks couldn't catch either.