fix: DrawTextOnPath renders tofu square between words in street labels - #3354

Problem

DrawTextOnPath was passing text through TransformText, which calls BreakText to insert \n characters at word boundaries for long labels. Since DrawTextOnPath is a single-line rendering call, Skia has no glyph for \n and renders it as a tofu square (□) — visible, for example, in Russian road names like "СТАДИОННАЯ УЛИЦА".

Fixes #3346

Root cause

TransformText was shared by both DrawText (point labels) and DrawTextOnPath (road labels). For point labels, the \n-based word-wrapping is correct — DrawText splits on \n and renders each line with a vertical offset. For path labels, the wrapping is both unnecessary (a path-length guard already skips labels that are too long) and harmful.

Changes

• SkiaCanvas.TransformText — added a wordWrap parameter (default true). When false, only case transforms (uppercase/lowercase) are applied; BreakText is skipped entirely.
• DrawTextOnPath — now calls TransformText(..., wordWrap: false), so no \n is ever produced for path text.
• Assembly.cs (new) — exposes internals to the test project via InternalsVisibleTo.
• Tests/Mapsui.Experimental.VectorTiles.Tests (new project) — unit tests for SkiaCanvas.TransformText covering: no \n when wordWrap: false, text preserved, uppercase/lowercase transforms, and empty-text edge case.
• .gitignore — added *.tmp to suppress MSBuild SDK resolver backup files.