Complete typography support across PowerBGInfo

[PrzemyslawKlys]

Summary

• add independent label, value, chart-title, and chart-value typography controls for font family, size, color, numeric weight, italic, underline variants, strikethrough variants, baseline, and casing
• preserve legacy Bold and Underline inputs while making the explicit numeric/style properties authoritative when both are supplied
• carry styles through the .NET API, PowerShell cmdlets and pipeline objects, JSON round trips, variable expansion, wrapping and measurement, chart rendering, generated help, examples, and validation samples
• preserve styled output across PNG, GIF, JPEG, BMP, PPM, and TIFF file exports; wallpaper and logon targets continue to normalize unsupported desktop formats to PNG

Example

New-BGInfoValue -Name 'Host' -BuiltinValue HostName `
    -FontFamilyName 'Segoe UI' -FontWeight 650 -Italic `
    -UnderlineStyle Double -StrikethroughStyle Dotted `
    -Baseline Superscript -TextCase TitleCase `
    -ValueColor Cyan -ValueFontWeight 400 -ValueTextCase ToggleCase

Compatibility and release boundary

Bold/ValueBold and Underline/ValueUnderline remain supported. Explicit FontWeight and UnderlineStyle values take precedence. Numeric weights accept the full 100-900 range, including intermediate CSS weights such as 550 and 650.

ChartForgeX 1.7.0 is now published and contains the shared typography API used by this change. PowerBGInfo consumes that public three-part release directly and has been revalidated through the normal package restore path; no unpublished dependency or downstream compatibility shim is used.

Validation

• 104 .NET tests and 48 PowerShell tests
• script, JSON, CLI, and PowerShell rendering parity
• supported raster-format style coverage, single-file CLI, NativeAOT generation, and direct visual inspection
• generated Markdown and MAML help parity

Fixes #69