Cherry-pick multi-font and bold/italic support from Support-multiple-fonts-and-modernize

[johnpierson]

Background

The Support-multiple-fonts-and-modernize branch contains both infrastructure/migration work and new user-facing features. This issue tracks cherry-picking the features only — no project format, build, or CI changes.

Reference branch: Support-multiple-fonts-and-modernize

This issue is assigned to an AI coding agent. Every step below is meant to be executed directly — no design decisions left open.

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Files to touch

File	Action
Text.cs	Add parameters to FromStringOriginAndScale, add GetInstalledFontNames()

No other files. Do not touch .csproj, packages.config, CI, or any build infrastructure.

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Checklist

1. Extend FromStringOriginAndScale with font, bold, and italic parameters

Current signature:

public static IEnumerable<Curve> FromStringOriginAndScale(string text, Point origin, double scale)

New signature:

public static IEnumerable<Curve> FromStringOriginAndScale(
    string text,
    Point origin,
    double scale,
    string fontFamily = "Arial",
    bool bold = false,
    bool italic = false)

Implementation requirements:

• Validate that fontFamily exists in Fonts.SystemFontFamilies. If not found, throw ArgumentException with a message that references GetInstalledFontNames() so the user knows how to discover valid values.
• Apply font weight: bold ? FontWeights.Bold : FontWeights.Medium
• Apply font style: italic ? FontStyles.Italic : FontStyles.Normal
• Default behavior (fontFamily = "Arial", bold = false, italic = false) must be identical to the current method — this is a non-breaking change.

2. Add GetInstalledFontNames() utility method

public static IList<string> GetInstalledFontNames()

• Query Fonts.SystemFontFamilies, extract the .Source property from each family.
• Return as an alphabetically sorted IList<string> (case-insensitive sort).
• No parameters. Windows-only (same as the rest of the library).

3. Add required using statements if missing

• using System; (for ArgumentException)
• using System.Linq; (for LINQ queries on SystemFontFamilies)

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Definition of done

• FromStringOriginAndScale accepts fontFamily, bold, and italic — all optional with defaults
• Calling FromStringOriginAndScale with no new arguments produces identical output to current behavior
• Passing an uninstalled font name throws ArgumentException with message referencing GetInstalledFontNames()
• GetInstalledFontNames() returns a non-empty, alphabetically sorted list on Windows
• No .csproj, CI, NuGet, or build file changes in this PR

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Notes

• Do not port the infrastructure/modernization changes from the source branch — those are tracked in Migrate DynamoText from .NET Framework 4.5 to .NET 8 #10.
• This PR should be a clean, minimal diff to Text.cs only.
• If this PR lands before Migrate DynamoText from .NET Framework 4.5 to .NET 8 #10, it targets the current net45 build. If Migrate DynamoText from .NET Framework 4.5 to .NET 8 #10 lands first, target net8.0-windows — the feature code is identical either way.