Symmetric with the existing DataContent overload. Handles self-contained data:
URIs by delegating to the DataContent path and does no file/network IO. For file:
and remote URIs it throws NotSupportedException, leaving native URL passthrough
(Mistral document_url, Azure DI uriSource) as an explicit open design question.

The method returns a rich OcrResult (markdown, tables, figures/images, blocks,
confidence, language), not plain text, so GetTextAsync was a misnomer. ExtractAsync
names the document-extraction operation accurately. Scoped to the Ocr/ types only;
ISpeechToTextClient.GetTextAsync is unrelated and unchanged.

Alternatives considered for maintainer discussion: GetDocumentAsync, AnalyzeAsync.

…ions

…ines

Complete the source rename across the OCR test suites in both
Microsoft.Extensions.AI.Abstractions.Tests and Microsoft.Extensions.AI.Tests, and
regenerate the two API baselines (which also reflect the round-2 members
ExtractFromUriAsync, OcrImage, and OcrPage.Images). Also fix pre-existing StyleCop/Sonar
violations in the OCR tests that were blocking the core test project from compiling.

Stream.CopyToAsync(Stream, CancellationToken) does not exist on net462/
netstandard2.0, so the 2-arg call failed to compile (CS1503) on the
net462 leg. Use the #if !NET conditional buffer-size overload, matching
the existing DataContent.cs convention.

Introduce OcrPoint and OcrBoundingBox readonly record structs and retype
OcrBoundingRegion.Polygon as IReadOnlyList<OcrPoint> with a typed
OcrBoundingBox GetBounds() return. This makes odd or empty vertex lists
unrepresentable (fixing the GetBounds inverted-bounds edge case) and reads
self-documenting, while still carrying a rotation-skewed quadrilateral.

Rename OcrPage.Index (zero-based) to OcrPage.PageNumber (one-based) so it
correlates directly with OcrBoundingRegion.PageNumber, matching Azure
Document Intelligence, PdfPig, and human page conventions, and removing the
off-by-one adjustments providers had to make.

Update the internal OcrDocumentReader and the OCR tests, and regenerate the
Microsoft.Extensions.AI.Abstractions API baseline.

…es, usage tokens

Continue the IOcrClient reshape ahead of API review (dotnet#7587/dotnet#7588).

- Replace parallel OcrPage.Blocks/Tables/Images with a single reading-order
  Elements list over a new polymorphic OcrElement base (OcrBlock/OcrTable/OcrImage
  derive); consumers project with OfType<T>().
- Add optional nested OcrTableCell.Elements for structured cell content; keep the
  Content string as a flat-text convenience.
- Convert OcrCoordinateUnit to a closed enum and add Point; add an
  OcrCoordinateOrigin enum; move both to document level (OcrResult/OcrPageResult)
  and remove the per-page CoordinateUnit.
- Keep OcrBlockKind and OcrTableCellKind as open structs; add RowHeader and
  RowSection well-known cell kinds.
- Add nullable Input/Output/TotalTokenCount to OcrUsage for the vision-LLM path.
- Rename Markdown to Text on OcrPage/OcrResult; drop response ModelId,
  OcrPage.Confidence, and OcrOptions.IncludeImages; FromRectangle takes float.
- Keep ToOcrResult/ToOcrResultAsync reducers and the convenience overloads as
  extension methods, matching the MEAI ChatResponseExtensions precedent.
- Regenerate the ApiChief baselines for the reshaped surface.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 19ea13dd-f444-4942-b751-162711478580

SPIKE-07/08 primary-source verification refuted the round-1 assumption that a
document uses one uniform coordinate unit. Google Document AI models
Page.Dimension{width,height,unit} per page, and Azure DI's per-page
DocumentPage.Unit is "pixel" for image inputs and "inch" for PDF, so one
analyze call over a mixed batch returns different units on different pages.

- Group OcrPage.Width/Height into a new OcrPageDimensions readonly record
  struct (the extent; an atomic pair several engines bundle).
- Move CoordinateUnit + CoordinateOrigin from the document level (OcrResult,
  OcrPageResult) onto OcrPage; they are siblings to the dimensions extent,
  together describing the per-page coordinate system.
- Drop the reducer's last-non-null coordinate carry-forward: pages already
  carry their own unit/origin.
- Defer continuous page-rotation angle (Azure-family-only) to
  AdditionalProperties for v1; element rotation is already carried losslessly
  by the polygon OcrBoundingRegion.
- Update per-page tests and regenerate the ApiChief baseline (32 public types).

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 19ea13dd-f444-4942-b751-162711478580

SPIKE-06 built an exhaustive 14-engine raw-output inventory to justify the
RawRepresentation/AdditionalProperties escape hatches, then a promote interview
resolved which recurring un-homed fields become first-class.

- Add BoundingRegion, Confidence, RawRepresentation, and AdditionalProperties to
  OcrTableCell, mirrored member-for-member from OcrElement. Five engines (Textract,
  Google Document AI, Azure DI, Adobe, Docling) emit per-cell geometry, and a cell
  has its own rectangle even when empty or padded. OcrTableCell deliberately does
  not derive from OcrElement (a cell is not a page-reading-order element) and no
  shared base type is extracted yet; mirroring the members keeps that a reversible
  way-station under [Experimental].
- Add [JsonIgnore] object? RawRepresentation to OcrPage. Every other node carries
  it; the page node was the lone exception. Because the page rides through
  ToOcrResult reduction, provider-native page data now survives into
  OcrResult.Pages, closing a silent per-page raw data-loss.
- Detected language is deferred (not promoted) to a standardized
  AdditionalProperties key rather than a lossy typed field.
- Add OCR tests for cell geometry round-trip and per-page raw survival; regenerate
  the ApiChief baseline (five additive members, no new types).

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 19ea13dd-f444-4942-b751-162711478580

Move the reshaped OCR surface out of Microsoft.Extensions.AI(.Abstractions)
into a standalone peer library, Microsoft.Extensions.DocumentExtraction,
mirroring VectorData / DataIngestion. OCR is document extraction rather than
an AI-branded concern, so it gets its own package + namespace
(Microsoft.Extensions.DocumentExtraction) with domain-noun naming
(Document*/DocumentExtraction*) instead of the MEAI-internal verb scheme.

- New Microsoft.Extensions.DocumentExtraction.Abstractions: the Document*
  model, IDocumentExtractionClient, DocumentExtractionResult/Options/
  ClientMetadata/PageResult, extensions, DelegatingDocumentExtractionClient.
- New Microsoft.Extensions.DocumentExtraction: builder + Logging/
  OpenTelemetry/ConfigureOptions delegating clients + DI/builder extensions,
  with self-contained internal telemetry helpers (no MEAI-core coupling).
- Remove the OCR types from Microsoft.Extensions.AI(.Abstractions) and shrink
  both API baselines accordingly (only OCR type-blocks removed; the manual
  params edits and JSONC comments are preserved byte-for-byte).
- Populate the two new Stage=normal baselines (peer precedent: VectorData
  ships a populated baseline for its [Experimental] surface).
- Repoint Microsoft.Extensions.DataIngestion's OcrDocumentReader onto
  DocumentExtraction.Abstractions.
- Add DiagnosticIds MEDE0001 for the new [Experimental] surface.
- Retarget all OCR tests to two new DocumentExtraction test projects.

Green across all five TFMs (netstandard2.0, net462, net8.0, net9.0,
net10.0); DocumentExtraction tests 31/31 + 29/29 on net8/9/10; the MEDI
OcrDocumentReader test stays green after the repoint.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 19ea13dd-f444-4942-b751-162711478580

Every packable library in the repo ships a README.md (auto-included as PackageReadmeFile on
pack); the two new DocumentExtraction packages were missing theirs, so packing failed with
NU5019. Add READMEs mirroring the DataIngestion peers, describing the document-extraction
capability and the Abstractions-vs-core package split.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 19ea13dd-f444-4942-b751-162711478580