fix(templates,ci,docs): unblock chart/pie-chart/dashboard-02, fix preview pipeline, correct component count

[Shewart]

Summary

Three things that needed to land together before tagging 0.3.0-alpha.4:

1. Three CLI templates have shipped uncompilable C# since 0.3.0-alpha.1. After shellui add chart, pie-chart, or dashboard-02, consumer projects fail dotnet build immediately. Root cause: incorrect quote escaping inside C# verbatim strings emitted by template Content strings.
2. Preview-pages workflow has been red for two weeks with Get Pages site failed. HttpError: Not Found — actions/configure-pages@v4 was failing because Pages isn't enabled on the repo and the action wasn't asked to enable it.
3. Every doc claimed "100 components" when the registry actually exposes 68 installable top-level components — the "100" was inflated by counting sub-components (SidebarTrigger, DialogContent, …) and variants (ButtonVariants, …) that auto-install as dependencies.

Maps to Fixes 2, 9, 10 in shellui-fixes-for-lib.md plus the preview-pipeline failure and the count audit you requested.

Changes

Template escape bugs (Fixes 2, 9, 10)

• src/ShellUI.Templates/Templates/ChartVariantsTemplate.cs — 16 JS-attribute quotes inside the tooltip Custom = @"..." block: ""x"" → """"x"""" (so the generated .cs carries the proper ""x"" verbatim-string escape).
• src/ShellUI.Templates/Templates/PieChartTemplate.cs — was using \""x\"" which decoded to \"x\" and produced both a compile error and visible backslashes in rendered HTML. Fixed to """"x"""".
• src/ShellUI.Templates/Templates/DashboardLayout02Template.cs:86 — unterminated empty-string literal: segments[0] == "")) → segments[0] == """")).
• src/ShellUI.Components/Components/PieChart.razor — same backslash bug in the live library; NuGet consumers were seeing class=\"custom-tooltip\" in rendered HTML.

Regression guard

• ShellUI.Tests/TemplateCompileTests.cs — Roslyn CSharpSyntaxTree.ParseText over each template's generated Content. Pure-C# templates parse whole content; Razor templates extract @code { … } via a quote/comment-aware brace-balancing tokenizer. When extraction fails (unterminated string ate the closing brace) it falls back to a class-wrapped parse filtered to literal-related Roslyn diagnostic IDs (CS1010, CS1002, CS1003, CS1026, CS1513, CS1525, CS1056) so the failure points right at the offending line.
• ShellUI.Tests/ShellUI.Tests.csproj — Microsoft.CodeAnalysis.CSharp 4.11.0.
• .github/workflows/ci.yml — smoke-test step packs the CLI, installs it, runs dotnet new blazor → shellui init → shellui add chart pie-chart dashboard-02 → dotnet build as an end-to-end guard for anything the syntactic check misses.

Preview-pages pipeline

• .github/workflows/preview-pages.yml — actions/configure-pages@v4 now passes enablement: true so the action creates the Pages site on first run instead of erroring with HttpError: Not Found. Requires pages: write on GITHUB_TOKEN, already set.

⚠️ Note: the preview app still has independent issues (hardcoded <base href="/"> won't work at /shellui/, hardcoded dark mode, only ~25 of 68 components covered). Those are scoped to fix/preview-app (branch 8) and not part of this PR. This PR only unblocks the workflow run itself.

Component count audit

Authoritative count from ComponentRegistry (IsAvailable = true, top-level only): 68 installable = 17 Form + 12 Layout + 7 Navigation + 8 Overlay + 13 Data Display + 9 Feedback + 2 Utility. Updated every doc that claimed otherwise:

• README.md — main banner, status section, category breakdowns (was internally inconsistent: section header claimed 14 Form but listed 13), shellui list example, comparison table, footer status line.
• docs/ARCHITECTURE.md — registry-stats line, category counts table.
• docs/COMPONENT_ROADMAP.md — status header, completed-list breakdown, timeline entry.
• docs/PROJECT_STATUS.md — version line, registry stats, category breakdowns, milestone targets.
• docs/CLI_SYNTAX.md, docs/QUICKSTART.md, docs/COMPARISON.md, docs/FAQ.md — inline "100" / "100+" references.
• VERSIONING_STRATEGY.md — current-release facts, single-source-of-truth list.
• src/ShellUI.CLI/README.md, src/ShellUI.Components/README.md, src/ShellUI.Templates/README.md — package-level claims.

Intentionally left alone:

• docs/RELEASE_NOTES.md historical sections — frozen archive of what we said at the time of each release.
• docs/PROJECT_STATUS.md future-state goals ("100+ components", "100+ community members") — aspirational, not current state.
• CSS color values like 0 0% 100% — those are HSL lightness, not counts.

Verification

• dotnet test ShellUI.Tests — 15/15 passing.
• Stash-and-retest of DashboardLayout02Template.cs:86 (removed the fix only) → test red-bars with CS1010: Newline in constant at 26,76. Restoring the fix returns to green. Confirms the guard bites.
• grep -n '\b100\b' **/*.md — remaining hits are all intentional (CSS values, future-state goals, historical release notes).

Test plan

• CI green (build + tests + smoke-test step)
• Preview-pages workflow runs to completion (Setup Pages step succeeds)
• Manual repro: pack CLI locally, install as tool, scaffold a fresh dotnet new blazor, run shellui init + shellui add chart pie-chart dashboard-02, then dotnet build — expect 0 errors
• Render a <PieChart> and confirm the hover tooltip's HTML no longer shows literal \" characters
• shellui list count matches the docs (68)