feat: ShellIcons.Maui preview, XAML path generator, static docs site on ShellDocs 0.1.7

[Shewart]

Summary

Adds the MAUI target from the design notes as an unpublished preview, and gets the docs site ready to deploy. ShellDocs 0.1.7-alpha's shelldocs build now outputs a real static site, so docs.yml can publish to shellicons.shellui.dev. No runtime SVG parsing on MAUI: icons are converted to path data at build time and drawn as native Path shapes. release.yml still packs only ShellIcons.Blazor.

ShellIcons.Maui (preview)

• Typed controls (<icons:ChevronRight />) for all 1,555 icons; each carries its own path data, so unused icons are trimmed
• Icon dispatcher with an IconName enum, so an icon can be a binding or a component parameter: <icons:Icon Name="{Binding StatusIcon}" />
• IconCatalog: tags and categories from Lucide's metadata, TryParse for ids, names and Lucide aliases ("home" → House), and Search
• Properties: Size, StrokeThickness, AbsoluteStroke, Color (bindable; black/white by app theme when unset), Title → SemanticProperties.Description. Icons are InputTransparent, so taps reach the host control.
• One xmlns for everything, https://shellicons.dev/maui; <icons:Image> coexists with MAUI's <Image>
• Builds for Android, iOS, Mac Catalyst and Windows

XAML path generator (ShellIcons.Generator.Xaml)

• Converts each SVG into one path in absolute coordinates: <path>, <circle>, <ellipse>, <rect> (corner radii), <line>, <polyline>, <polygon>
• The path parser handles run-together numbers, arc flags without separators, and shorthand curves (S/T)
• fill="currentColor" shapes get a second, filled path; every other icon is one native view
• At runtime the pre-converted path becomes geometry once per icon and is shared by every control showing it
• Aspect=None plus a scale transform keeps icons on Lucide's 24×24 grid; the stroke width is scaled separately
• New diagnostics for custom icons: SHELLICONS002 (unsupported SVG such as <g> or transform), SHELLICONS004 (name can't be an enum member), SHELLICONS005 (shape outside the viewBox, dropped)
• The Blazor and MAUI generators share one naming rule (Naming.KebabToPascal)

Docs site (ShellDocs 0.1.3 → 0.1.7-alpha)

• Static build: every page is prerendered to plain HTML. docs.yml pins the CLI and passes --site-url, which adds sitemap.xml, robots.txt and og: tags.
• Icon browser: moved from /icons to /docs/icons as a component used from content/docs/icons.md. The build only prerenders content/ pages, so the old route would have 404'd.
• Icon search: works after in-app navigation (the old inline script only ran on a full page load)
• App.razor: plain asset paths instead of the template's hashed @Assets[…] URLs, which 404 on a static host (the scoped-CSS bundle among them)
• Page titles: now update on in-app navigation (<HeadOutlet> gets the same render mode as <Routes>)
• Highlighting: XAML, CSS and PowerShell code blocks
• Content: a MAUI section (getting started, names & catalog, how rendering works) and a full diagnostics table; the intro and generator pages now recommend <ChevronRightIcon />

Solutions and CI

• MAUI projects are in a new ShellIcons.Maui.slnx, so ShellIcons.slnx still builds without the MAUI workloads
• New Windows CI job: installs the MAUI workload, builds all five targets, runs the MAUI tests

Repo docs

• CHANGELOG.md: Unreleased covers the merged Blazor changes and this PR
• RELEASING.md: the release flow for maintainers (bump version + CHANGELOG, tag, approve the release environment); owner-only setup is marked as done
• README: status table, MAUI quickstart, how to build the static docs
• catalog/custom/README.md: which SVG features convert to MAUI
• .gitignore: now covers publish/ (static docs output) and nupkgs/

Fixes found along the way

• Lucide 0.475.0's save-off.svg has a stray shape entirely outside the viewBox. Browsers clip it; a native Path would draw it beside the icon, so it's dropped for MAUI.

Breaking changes

• None for ShellIcons.Blazor consumers. The docs site's icon browser URL changes from /icons to /docs/icons, but the site hasn't been deployed yet.

Test plan

• dotnet build ShellIcons.slnx: 0 warnings, 0 errors
• dotnet test ShellIcons.slnx: 101/101 (57 generator, 44 Blazor). New tests cover the path parser, the shape converter, the metadata reader and off-canvas detection.
• dotnet build ShellIcons.Maui.slnx: 0 warnings, 0 errors for net10.0, Android, iOS, Mac Catalyst and Windows
• dotnet test tests/ShellIcons.Maui.Tests: 34/34, headless. Includes:
  • a compiled XAML page (xmlns, string → IconName, icons:Image next to MAUI's Image)
  • a check that parses every icon into MAUI geometry and keeps every endpoint on the grid (this found the save-off shape)
• shelldocs build: 16 pages prerendered
• Output served as plain files and checked in a browser:
  • search ("circle" → 55 of 1,555)
  • sidebar expand/collapse
  • stylesheets loading, no stray reconnect dialogs
• Docs dev server: home → "Browse icons" by click, then search; page titles update on navigation
• Icon browser click-to-copy (automation can't read the clipboard)
• Android / iOS / macOS visual check of ShellIcons.Maui (not verified yet)

Follow-ups

• Look at ShellIcons.Maui on devices, give it its own package readme, and add it to release.yml (Windows or macOS job with the MAUI workload)
• Consumer-selectable icon subsets: needs the generator and catalog shipped inside the package
• ShellDocs: use a folder's meta.json title (the sidebar shows "Maui"), prerender custom @page routes, and fix the scaffolded App.razor. Tracked in shelldocs' SHELLDOCS_FIXES.md.
• Bump <Version> in Directory.Build.props before the next tag. 0.1.0-alpha is already on NuGet.
• ShellUI Native can switch its interim icon component to ShellIcons.Maui once it ships (same IconName / Icon names)