Doclang backlog

[vagenas]

High prio:

• address key value regions (consolidate FormItem / KeyValueItem (KEY_VALUE_REGION) (feat: introduce field data model incl. Doclang serialization #519)
• align w.r.t. tokenizer
• fix table cell content deserialization (fix(DocLang): fix table cell <content> deserialization #512)
• fix document re-indexing (fix: fix document re-indexing #510)
• fix DocTags picture meta deserialization (fix(DocTags): fix deserialization to populate picture meta fields #505)
• review checkboxes (fix(Doclang): fix checkbox serialization #503)
• review chart serialization (compared to table serialization) (test(Doclang): add chart serialization test #498)
• align handling of default resolution (location) (fix(IDocTags): fix default location resolution handling #492)
• rich tables / nested tables (feat(IDocTags): add rich table support #491)
• leading / trailing whitespaces (feat(IDocTags): add content wrapping for handling whitespace #489)
• finalize outmost element name (chore: rename IDocTags to Doclang #494)

Medium:

• content layer (e.g. furniture) not captured in Doclang (feat(Doclang): add content layer support #568)
• map HANDWRITTEN label to new Doclang element (similar to bold, italics) (feat: Add HANDWRITTEN_TEXT label support #561)
• include allowed layer values to standard
• govern picture classes (currently str)
• alternative export mode where KVs are shown as just text
• inline code issue: conflict between <inline class="code"> and <code class="Python"> (chore(Doclang): remove inline element #517)
• support extended bounding polygons (beyond non-rotated rectangles) (see feat: extend bounding box #348)
  • (on draft level, could just be by generalizing from 4=22 location tokens (interpreted as rectangle) to N2 tokens for any arbitrary polygon with N vertices)
• use defusedxml? (fix: switch xml parsing #509)
• align image ref mode on Doclang serialization (fix(Doclang): align image mode, defaulting to placeholder #506)
• image URI serialization (fix(Doclang): fix image URI serialization #504)
• track CVAT test output (fix: populate picture meta, track Doclang output docling-cvat-tools#8)

Low:

• add radio button support (update: not for now)
• XML Schema / DTD?
• page breaks
• line breaks
• check formatting:hyperlink
• list languages in draft (as subset of Linguist vX.Y.Z)
  • extend list to support e.g. Markdown?
  • define clearly how non-programming log/console-like content is to be captured (e.g. code with unset language or Shell?)
• cross-provenance content
• cross-page content
• sync elements between IDocTags & draft (e.g. content)
• converge between <content xml:space="preserve"> and {<content>+ other way of signalizing whitespace preservation e.g. via ATTLIST, XML schema, convention etc.}
• clarify dropping of include_formatting serializer switch
• update draft: e.g. content element, base64 element, ...