chore: Add namespace infrastructure for remaining SVG2 chapters

Create namespace infrastructure (without implementations) for:
- Chapter 6: Styling (CSS and presentation)
- Chapter 7: Geometry (Positioning and sizing)
- Chapter 8: Coordinates (Coordinate systems and transforms)
- Chapter 9: Paths (Path elements and data)
- Chapter 11: Text (Text content elements)
- Chapter 12: Embedded (Embedded content)
- Chapter 13: Painting (Fill, stroke, markers)
- Chapter 15: Scripting (Interactivity and events)
- Chapter 16: Linking (Hyperlinks and views)

Each namespace includes:
- Complete chapter documentation
- W3C spec references
- Overview of planned elements
- Cross-references to related namespaces

Infrastructure allows for systematic implementation of
remaining SVG2 specification chapters.

Updated README to show implementation status:
- ✓ Fully implemented (4 chapters)
- Infrastructure ready (8 chapters)

Build verified: All 50 tests passing

Author: coenttb

README.md

@@ -14,27 +14,27 @@ Foundation-free Swift implementation of W3C SVG 2 specification.
 This package implements the [W3C SVG 2 specification](https://www.w3.org/TR/SVG2/) with namespaced types that directly map to SVG 2 chapters:
 
 ### Foundational
-- **Types** (Chapter 4): Basic data types - Length, Color, Transform, ViewBox
-- **Document** (Chapter 5): Document structure elements (coming soon)
-- **Styling** (Chapter 6): CSS and presentation (coming soon)
+- **Types** (Chapter 4): Basic data types - Length, Color, Transform, ViewBox ✓
+- **Document** (Chapter 5): SVG, Group, Defs, Symbol, Use ✓
+- **Styling** (Chapter 6): CSS and presentation (infrastructure ready)
 
 ### Geometry & Coordinates
-- **Geometry** (Chapter 7): Positioning and sizing properties (coming soon)
-- **Coordinates** (Chapter 8): Coordinate systems and transforms (coming soon)
+- **Geometry** (Chapter 7): Positioning and sizing properties (infrastructure ready)
+- **Coordinates** (Chapter 8): Coordinate systems and transforms (infrastructure ready)
 
 ### Graphics Elements
-- **Paths** (Chapter 9): Path elements and data (coming soon)
-- **Shapes** (Chapter 10): Circle, Rectangle, Ellipse, Line
-- **Text** (Chapter 11): Text content elements (coming soon)
-- **Embedded** (Chapter 12): Embedded content (coming soon)
+- **Paths** (Chapter 9): Path elements and data (infrastructure ready)
+- **Shapes** (Chapter 10): Circle, Rectangle, Ellipse, Line, Polyline, Polygon ✓
+- **Text** (Chapter 11): Text content elements (infrastructure ready)
+- **Embedded** (Chapter 12): Embedded content (infrastructure ready)
 
 ### Rendering
-- **Painting** (Chapter 13): Fill, stroke, markers (coming soon)
-- **PaintServers** (Chapter 14): Gradients and patterns (coming soon)
+- **Painting** (Chapter 13): Fill, stroke, markers (infrastructure ready)
+- **PaintServers** (Chapter 14): LinearGradient, RadialGradient, Stop, Pattern ✓
 
 ### Interactivity
-- **Scripting** (Chapter 15): Interactivity and events (coming soon)
-- **Linking** (Chapter 16): Hyperlinks and views (coming soon)
+- **Scripting** (Chapter 15): Interactivity and events (infrastructure ready)
+- **Linking** (Chapter 16): Hyperlinks and views (infrastructure ready)
 
 ## Installation
 

Sources/W3C SVG/W3C_SVG2.Coordinates.swift

@@ -0,0 +1,37 @@
+//
+//  W3C_SVG2.Coordinates.swift
+//  swift-w3c-svg
+//
+//  Chapter 8: Coordinate Systems, Transformations and Units
+//
+
+extension W3C_SVG2 {
+    /// Chapter 8: Coordinate Systems, Transformations and Units
+    ///
+    /// W3C SVG 2 Chapter 8
+    /// https://www.w3.org/TR/SVG2/coords.html
+    ///
+    /// The Coordinates namespace contains additional coordinate system utilities
+    /// and transformation helpers beyond the basic Transform type.
+    ///
+    /// ## Overview
+    ///
+    /// This namespace provides:
+    /// - Advanced transformation matrices
+    /// - Coordinate space conversions
+    /// - Unit conversion utilities
+    /// - Bounding box computations
+    ///
+    /// ## Topics (To Be Implemented)
+    ///
+    /// - CTM (Current Transformation Matrix) calculations
+    /// - Screen CTM computations
+    /// - Point and matrix transformations
+    /// - Unit-aware measurements
+    ///
+    /// ## See Also
+    ///
+    /// - ``Types.Transform``: Basic transform type (Chapter 4)
+    /// - ``Geometry``: Geometry properties (Chapter 7)
+    public enum Coordinates {}
+}

Sources/W3C SVG/W3C_SVG2.Embedded.swift

@@ -0,0 +1,48 @@
+//
+//  W3C_SVG2.Embedded.swift
+//  swift-w3c-svg
+//
+//  Chapter 12: Embedded Content
+//
+
+extension W3C_SVG2 {
+    /// Chapter 12: Embedded Content
+    ///
+    /// W3C SVG 2 Chapter 12
+    /// https://www.w3.org/TR/SVG2/embedded.html
+    ///
+    /// The Embedded namespace contains elements for embedding external content
+    /// within SVG documents, including raster images and foreign objects.
+    ///
+    /// ## Overview
+    ///
+    /// SVG supports embedding:
+    /// - Raster images (PNG, JPEG, etc.) via image element
+    /// - Arbitrary XML/HTML content via foreignObject
+    /// - Other SVG documents via image or nested svg
+    ///
+    /// ## Elements (To Be Implemented)
+    ///
+    /// - Image element for raster images
+    /// - ForeignObject element for HTML/XML content
+    ///
+    /// ## Image Element
+    ///
+    /// The image element embeds raster images:
+    /// - Supports common formats (PNG, JPEG, SVG)
+    /// - Position and size via x, y, width, height
+    /// - preserveAspectRatio for scaling control
+    ///
+    /// ## ForeignObject Element
+    ///
+    /// The foreignObject element embeds non-SVG content:
+    /// - HTML elements and CSS styling
+    /// - MathML for mathematical notation
+    /// - Custom XML namespaces
+    ///
+    /// ## See Also
+    ///
+    /// - ``Document``: Document structure (Chapter 5)
+    /// - ``Shapes``: Basic shapes (Chapter 10)
+    public enum Embedded {}
+}

Sources/W3C SVG/W3C_SVG2.Geometry.swift

@@ -0,0 +1,37 @@
+//
+//  W3C_SVG2.Geometry.swift
+//  swift-w3c-svg
+//
+//  Chapter 7: Coordinate Systems, Transformations and Units
+//
+
+extension W3C_SVG2 {
+    /// Chapter 7: Coordinate Systems, Transformations and Units
+    ///
+    /// W3C SVG 2 Chapter 7
+    /// https://www.w3.org/TR/SVG2/coords.html
+    ///
+    /// The Geometry namespace contains types and properties related to coordinate
+    /// systems, transformations, and unit specifications in SVG.
+    ///
+    /// ## Overview
+    ///
+    /// SVG uses coordinate systems for positioning and sizing:
+    /// - User coordinate system
+    /// - Viewport coordinate system
+    /// - Object bounding box units
+    /// - Nested coordinate systems via viewBox
+    ///
+    /// ## Topics (To Be Implemented)
+    ///
+    /// - Coordinate system transformations
+    /// - Units (px, em, ex, pt, pc, cm, mm, in, %)
+    /// - Bounding box calculations
+    /// - Nested viewport establishment
+    ///
+    /// ## See Also
+    ///
+    /// - ``Types``: Basic data types (Chapter 4)
+    /// - ``Document``: Document structure (Chapter 5)
+    public enum Geometry {}
+}

Sources/W3C SVG/W3C_SVG2.Linking.swift

@@ -0,0 +1,55 @@
+//
+//  W3C_SVG2.Linking.swift
+//  swift-w3c-svg
+//
+//  Chapter 16: Linking
+//
+
+extension W3C_SVG2 {
+    /// Chapter 16: Linking
+    ///
+    /// W3C SVG 2 Chapter 16
+    /// https://www.w3.org/TR/SVG2/linking.html
+    ///
+    /// The Linking namespace contains elements for creating hyperlinks and
+    /// references within and between SVG documents.
+    ///
+    /// ## Overview
+    ///
+    /// SVG linking supports:
+    /// - Hyperlinks to external resources via anchor (a) element
+    /// - Fragment identifiers for internal navigation
+    /// - View specifications for zooming and panning
+    /// - IRI references for resource linking
+    ///
+    /// ## Elements (To Be Implemented)
+    ///
+    /// - Anchor (a) element for hyperlinks
+    /// - View element for view specifications
+    ///
+    /// ## Link Properties (To Be Implemented)
+    ///
+    /// - href: Target URL or IRI
+    /// - target: Browsing context
+    /// - download: Download hint
+    ///
+    /// ## View Specifications (To Be Implemented)
+    ///
+    /// - viewBox for view definition
+    /// - preserveAspectRatio for scaling
+    /// - zoomAndPan for user interaction
+    ///
+    /// ## IRI References
+    ///
+    /// SVG uses IRIs (Internationalized Resource Identifiers) for:
+    /// - Paint servers (url(#gradient))
+    /// - Clip paths and masks
+    /// - Filters and effects
+    /// - Text paths and use elements
+    ///
+    /// ## See Also
+    ///
+    /// - ``Document``: Document structure (Chapter 5)
+    /// - ``Scripting``: Interactivity (Chapter 15)
+    public enum Linking {}
+}

Sources/W3C SVG/W3C_SVG2.Painting.swift

@@ -0,0 +1,53 @@
+//
+//  W3C_SVG2.Painting.swift
+//  swift-w3c-svg
+//
+//  Chapter 13: Painting — Filling, Stroking and Marker Symbols
+//
+
+extension W3C_SVG2 {
+    /// Chapter 13: Painting — Filling, Stroking and Marker Symbols
+    ///
+    /// W3C SVG 2 Chapter 13
+    /// https://www.w3.org/TR/SVG2/painting.html
+    ///
+    /// The Painting namespace contains elements and types related to how SVG
+    /// graphics are painted, including fill and stroke properties, and markers
+    /// for path vertices.
+    ///
+    /// ## Overview
+    ///
+    /// SVG painting encompasses:
+    /// - Fill properties (color, opacity, fill-rule)
+    /// - Stroke properties (color, width, linecap, linejoin, dasharray)
+    /// - Marker symbols for path vertices
+    /// - Paint order control
+    ///
+    /// ## Fill Properties (To Be Implemented)
+    ///
+    /// - fill: Paint server or color
+    /// - fill-opacity: Opacity of fill
+    /// - fill-rule: evenodd or nonzero winding
+    ///
+    /// ## Stroke Properties (To Be Implemented)
+    ///
+    /// - stroke: Paint server or color
+    /// - stroke-width: Width of stroke
+    /// - stroke-linecap: butt, round, or square
+    /// - stroke-linejoin: miter, round, or bevel
+    /// - stroke-dasharray: Dash pattern
+    /// - stroke-dashoffset: Dash pattern offset
+    /// - stroke-opacity: Opacity of stroke
+    ///
+    /// ## Markers (To Be Implemented)
+    ///
+    /// - Marker element for vertex symbols
+    /// - marker-start, marker-mid, marker-end properties
+    /// - Auto-orientation and scaling
+    ///
+    /// ## See Also
+    ///
+    /// - ``PaintServers``: Gradients and patterns (Chapter 14)
+    /// - ``Types.Color``: Color values (Chapter 4)
+    public enum Painting {}
+}

Sources/W3C SVG/W3C_SVG2.Paths.swift

@@ -0,0 +1,49 @@
+//
+//  W3C_SVG2.Paths.swift
+//  swift-w3c-svg
+//
+//  Chapter 9: Paths
+//
+
+extension W3C_SVG2 {
+    /// Chapter 9: Paths
+    ///
+    /// W3C SVG 2 Chapter 9
+    /// https://www.w3.org/TR/SVG2/paths.html
+    ///
+    /// The Paths namespace contains the path element and path data specification
+    /// for creating complex vector graphics with lines, curves, and arcs.
+    ///
+    /// ## Overview
+    ///
+    /// Paths are the most powerful drawing primitive in SVG, enabling:
+    /// - Arbitrary line segments (moveto, lineto)
+    /// - Cubic and quadratic Bézier curves
+    /// - Elliptical arc curves
+    /// - Closed subpaths
+    ///
+    /// ## Elements (To Be Implemented)
+    ///
+    /// - Path element
+    /// - Path data command types (M, L, H, V, C, S, Q, T, A, Z)
+    /// - Path data parsing and generation
+    ///
+    /// ## Path Commands
+    ///
+    /// - M/m: moveto
+    /// - L/l: lineto
+    /// - H/h: horizontal lineto
+    /// - V/v: vertical lineto
+    /// - C/c: cubic Bézier curve
+    /// - S/s: smooth cubic Bézier curve
+    /// - Q/q: quadratic Bézier curve
+    /// - T/t: smooth quadratic Bézier curve
+    /// - A/a: elliptical arc
+    /// - Z/z: closepath
+    ///
+    /// ## See Also
+    ///
+    /// - ``Shapes``: Basic shapes (Chapter 10)
+    /// - ``Types``: Basic data types (Chapter 4)
+    public enum Paths {}
+}

Sources/W3C SVG/W3C_SVG2.Scripting.swift

@@ -0,0 +1,46 @@
+//
+//  W3C_SVG2.Scripting.swift
+//  swift-w3c-svg
+//
+//  Chapter 15: Scripting and Interactivity
+//
+
+extension W3C_SVG2 {
+    /// Chapter 15: Scripting and Interactivity
+    ///
+    /// W3C SVG 2 Chapter 15
+    /// https://www.w3.org/TR/SVG2/interact.html
+    ///
+    /// The Scripting namespace contains elements and interfaces related to
+    /// interactivity, event handling, and scripting in SVG documents.
+    ///
+    /// ## Overview
+    ///
+    /// SVG interactivity includes:
+    /// - Event attributes (onclick, onmouseover, etc.)
+    /// - Script element for embedded scripts
+    /// - DOM interfaces for programmatic access
+    /// - Cursor and pointer-events control
+    ///
+    /// ## Elements (To Be Implemented)
+    ///
+    /// - Script element for JavaScript/ECMAScript
+    ///
+    /// ## Event Handling (To Be Implemented)
+    ///
+    /// - Mouse events (click, mousedown, mouseup, mousemove, etc.)
+    /// - Focus events (focusin, focusout)
+    /// - Keyboard events (keydown, keyup, keypress)
+    /// - Document events (load, unload, abort, error, resize, scroll)
+    ///
+    /// ## Pointer Events (To Be Implemented)
+    ///
+    /// - pointer-events property
+    /// - Touch and pen input handling
+    ///
+    /// ## See Also
+    ///
+    /// - ``Document``: Document structure (Chapter 5)
+    /// - ``Linking``: Hyperlinks (Chapter 16)
+    public enum Scripting {}
+}