feat: Implement ZEP 8 URL syntax support for zarr-python

[ianhi]

Continuation of @jhamman's #3369 with addressing my review comments
Claude summary of the changes on top of Joe's PR:

1. Format Propagation ✅

• Zarr format segments (zarr2:, zarr3:) now propagate from URLs to array/group creation
• Modified resolve_url_with_path() to return (Store, str, ZarrFormat | None)
• Updated all API functions (create, open, open_array, open_group) to use URL format when user doesn't specify
• 15 new tests for format propagation with comprehensive on-disk verification

2. Nested Adapter Chains ✅

• Implemented recursive URL resolution in ZipAdapter to support nested adapters
• Added _create_nested_zip_store() method that handles nested ZEP 8 URLs
• Enables ZEP 8 spec examples like file:outer.zip|zip:inner.zip|zip:data.zarr
• 8 comprehensive tests covering arrays, groups, edge cases, and complex hierarchies

3. Exception Handling Cleanup ✅

• Removed all broad except Exception: handlers from _zep8.py
• Simplified control flow by removing redundant try-except blocks
• Only specific KeyError exceptions caught where appropriate
• Parser exceptions now propagate naturally for easier debugging

4. URL Logic Refactoring

• Fixed s3+https scheme handling
• Improved URL validation logic
• Better separation of concerns between parsing and resolution

5. Storage Options Validation

• Enhanced storage_options handling and validation
• Better error messages for invalid configurations

Test Coverage: 167 tests passing (1 skipped), up from ~150 tests

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Missing ZEP 8 Features Analysis

Based on the ZEP 8 specification, here are the adapter schemes defined vs. implemented:

✅ Currently Implemented (9 adapters)

• file: - FileSystemAdapter
• memory: - MemoryAdapter
• https:, http: - RemoteAdapter
• s3:, s3+http:, s3+https: - S3Adapter (via RemoteAdapter)
• gs: - GCSAdapter (via RemoteAdapter)
• zip: - ZipAdapter
• log: - LoggingAdapter (custom, not in spec)
• zarr2:, zarr3:, zarr: - Format segments (handled by resolution layer)

❌ Missing from Spec (11 adapters)

Storage/Database Adapters:

1. ocdbt: - OCDBT format (versioned KV store)
2. icechunk: - Icechunk format (versioned Zarr store)

Compression Adapters:
3. gzip: - Transparent gzip decompression
4. zstd: - Transparent zstd decompression

Data Format Adapters:
5. n5: - N5 format support
6. tiff:, jpeg:, png:, bmp:, avif:, webp: - Image format adapters
7. neuroglancer-precomputed: - Neuroglancer format
8. json: - JSON pointer access

Utility Adapters:
9. byte-range:start-end - Byte range extraction
10. ..: - Parent directory traversal (for relative URLs)

Other Missing Features:

• Relative URL pipeline syntax - Spec lines 489-543 (explicitly noted as not supported in zarr-python
  implementation notes)
• Format auto-detection - Spec lines 420-443 (MAY support, optional feature)