HwpForge Core: format-independent Document Object Model.

This crate defines the universal document structure used across all HwpForge format conversions. It is the Anvil in the Forge metaphor -- the surface on which all documents are shaped.

Architecture

Core sits one layer above Foundation:

foundation (primitives: HwpUnit, Color, Index<T>)
    |
    v
core (this crate: Document, Section, Paragraph, Run)
    |
    v
blueprint (styles: CharShape, ParaShape, Template)
    |
    v
smithy-* (format codecs: HWPX, HWP5, Markdown)

Core has zero knowledge of XML, binary formats, or Markdown. It references style definitions by branded indices (Foundation's CharShapeIndex, ParaShapeIndex) without depending on Blueprint.

Document Lifecycle (Typestate)

Document<Draft>  --(validate)-->  Document<Validated>
   (mutable)                         (immutable)

• [Draft] documents can be modified (add sections, set metadata).
• [Validated] documents are structurally sound and ready for export.
• Deserialization always produces Draft (must re-validate).

DOM Hierarchy

Document
  +-- Metadata
  +-- Section[]
        +-- PageSettings
        +-- Paragraph[]
              +-- Run[]
                    +-- RunContent
                          +-- Text(String)
                          +-- Table(Box<Table>)
                          +-- Image(Image)
                          +-- Control(Box<Control>)

Examples

use hwpforge_core::*;
use hwpforge_core::run::Run;
use hwpforge_core::section::Section;
use hwpforge_core::paragraph::Paragraph;
use hwpforge_foundation::{CharShapeIndex, ParaShapeIndex};

let mut doc = Document::new();
doc.add_section(Section::with_paragraphs(
    vec![Paragraph::with_runs(
        vec![Run::text("Hello, HwpForge!", CharShapeIndex::new(0))],
        ParaShapeIndex::new(0),
    )],
    PageSettings::a4(),
));

let validated = doc.validate().unwrap();
assert_eq!(validated.section_count(), 1);