Add Deep Zoom test resources and sample tile collections

[mattleibow]

Add DZI/DZC format test data, CXML PivotViewer collection metadata, and pre-generated tile images for Deep Zoom and PivotViewer development and testing.

Collections (11,615 files total)

Collection	Files	Size	Contents
buxton	1	416K	CXML PivotViewer collection
conceptcars	8,451	61M	298-item DZC collection with full tile pyramids (8,148 JPG tiles) + CXML
hungarian-blog	853	5.9M	50-item DZC collection (Hungarian food/recipe blog) with full tile pyramids (801 JPG tiles) + CXML
msdnmagazine	1	4.1M	CXML PivotViewer collection
nigeria-state	761	10M	31-item DZC collection with tile pyramids (727 JPG tiles) + CXML
sample	2	8K	Minimal single DZI image with one tile (integration test data)
shapes	14	100K	Geometry DZC collections with small tile sets + CXML
ski-resorts	140	1.1M	10-item DZC collection with tile pyramids + CXML
stockport	12	164K	Small DZC collection with tiles + CXML
testgrid	1,374	10M	Complete 14-level DZI tile pyramid (1,373 PNG tiles) for visual testing
venues	1	5.8M	CXML PivotViewer collection

Schemas

File	Description
DeepZoomSchema.xsd	XSD schema for DZI/DZC Deep Zoom XML formats
DeepZoomSchema.cs	Generated C# classes from the DZI/DZC schema
PivotImageCollectionMetadata.xsd	XSD schema for CXML PivotViewer collections
PivotRemoteCollection.xsd	XSD schema for remote PivotViewer collections
PivotImageCollectionMetadata_PivotRemoteCollection_DeepZoomSchema.cs	Generated C# classes from PivotViewer + DeepZoom schemas

Purpose

These resources are used by:

• Deep Zoom library test suite (SkiaSharp.Extended.DeepZoom.Tests)
• MAUI and Blazor sample apps
• Future PivotViewer implementation

Split out from #366 to make code review more manageable.

[Copilot]

Pull request overview

Adds Deep Zoom (DZI/DZC) and PivotViewer (CXML) sample/test resources to support Deep Zoom library testing and future PivotViewer work.

Changes:

• Added multiple .dzi Deep Zoom image descriptors for the collection-dz resource set.
• Added a collection-dz.cxml PivotViewer collection metadata file referencing the DZC image base.
• Introduced facet/category metadata and per-item facet values for sample filtering scenarios.

Reviewed changes

Copilot reviewed 20 out of 11615 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
resources/collections/collection-dz/deepzoom/0.dzi	Adds Deep Zoom DZI metadata for image 0
resources/collections/collection-dz/deepzoom/1.dzi	Adds Deep Zoom DZI metadata for image 1
resources/collections/collection-dz/deepzoom/2.dzi	Adds Deep Zoom DZI metadata for image 2
resources/collections/collection-dz/deepzoom/10.dzi	Adds Deep Zoom DZI metadata for image 10
resources/collections/collection-dz/deepzoom/11.dzi	Adds Deep Zoom DZI metadata for image 11
resources/collections/collection-dz/deepzoom/12.dzi	Adds Deep Zoom DZI metadata for image 12
resources/collections/collection-dz/deepzoom/13.dzi	Adds Deep Zoom DZI metadata for image 13
resources/collections/collection-dz/deepzoom/14.dzi	Adds Deep Zoom DZI metadata for image 14
resources/collections/collection-dz/deepzoom/15.dzi	Adds Deep Zoom DZI metadata for image 15
resources/collections/collection-dz/deepzoom/16.dzi	Adds Deep Zoom DZI metadata for image 16
resources/collections/collection-dz/deepzoom/17.dzi	Adds Deep Zoom DZI metadata for image 17
resources/collections/collection-dz/deepzoom/18.dzi	Adds Deep Zoom DZI metadata for image 18
resources/collections/collection-dz/deepzoom/19.dzi	Adds Deep Zoom DZI metadata for image 19
resources/collections/collection-dz/deepzoom/20.dzi	Adds Deep Zoom DZI metadata for image 20
resources/collections/collection-dz/deepzoom/21.dzi	Adds Deep Zoom DZI metadata for image 21
resources/collections/collection-dz/deepzoom/22.dzi	Adds Deep Zoom DZI metadata for image 22
resources/collections/collection-dz/deepzoom/23.dzi	Adds Deep Zoom DZI metadata for image 23
resources/collections/collection-dz/deepzoom/24.dzi	Adds Deep Zoom DZI metadata for image 24
resources/collections/collection-dz/deepzoom/25.dzi	Adds Deep Zoom DZI metadata for image 25
resources/collections/collection-dz/collection-dz.cxml	Adds PivotViewer CXML collection metadata referencing collection-dz.dzc

[Copilot]

ServerFormat="Default" is not part of the standard Deep Zoom 2009 DZI <Image> definition; if these resources are validated against DeepZoomSchema.xsd (or deserialized with schema-derived classes), this extra attribute can cause validation failures / schema mismatch. Consider removing ServerFormat from the DZI resources (or, if it’s required for your tooling, update the schema/classes and tests to explicitly allow it). Also apply consistently across the other resources/collections/collection-dz/deepzoom/*.dzi files added in this PR.