Retire GeneratedSource once CodeBlocker emits deterministic newlines #184

Summary

GeneratedSource.cs exists solely to undo a CodeBlocker behaviour:

internal static string NormalizeLineEndings(string source) =>
    source.Replace("\r\n", "\n").Replace("\n", "\r\n");

Its own remarks say why:

ktsu.CodeBlocker writes through IndentedTextWriter, which uses Environment.NewLine — so the same metadata produced CRLF output on Windows and LF output on Linux. Generator output under Semantics.Quantities/Generated/ is committed to the repository and verified by CI, so it has to be byte-identical regardless of who builds it.

That is a workaround for a gap in the writer, not a Semantics concern. ktsu-dev/CodeBlocker#81 fixes it at the source.

Tasks

• Once Make output line endings deterministic and configurable CodeBlocker#81 ships, configure the newline at CodeBlocker construction (CRLF, to match end_of_line = crlf in .editorconfig and *.cs text eol=crlf in .gitattributes).
• Delete NormalizeLineEndings and either delete GeneratedSource.Add or keep it as a thin context.AddSource wrapper if it earns its place.
• Related: the template model's body-layout logic splits on Environment.NewLine (Close the correctness and coverage gaps in the C# template object model CodeBlocker#85, item 4). That is a second host dependency the normalization pass does not fix — a method body assembled on Linux can be laid out differently from the same body on Windows, and post-hoc newline rewriting cannot undo a layout decision. Confirm this is closed out before deleting the pass.
• Consider whether verify-generated.yml can then drop runs-on: windows-latest — it is pinned there today only so git's autocrlf matches the committed CRLF endings.

Acceptance criteria

• Building Semantics.Quantities on Linux and on Windows produces byte-identical files under Generated/.
• verify-generated passes with no normalization pass in the generator.

Context

Part of #181. Blocked on ktsu-dev/CodeBlocker#81 and ktsu-dev/CodeBlocker#85.