fix: Correct word width and space calculations (#963)

## Summary

**What is the goal of this PR?**

This change fixes an issue I noticed while reading where occasionally,
especially in italics, some words would have too much space between
them. The problem was that word width calculations were including any
negative X overhang, and combined with a space before the word, that can
lead to an inconsistently large space.

## Additional Context

Screenshots of some problematic text:

| In CrossPoint 1.0 | With this change |
| -- | -- |
| <img
src="https://github.com/user-attachments/assets/87bf0e4b-341f-4ba9-b3ea-38c13bd26363"
width="400" /> | <img
src="https://github.com/user-attachments/assets/bf11ba20-c297-4ce1-aa07-43477ef86fc2"
width="400" /> |

---

### AI Usage

While CrossPoint doesn't have restrictions on AI tools in contributing,
please be transparent about their usage as it
helps set the right context for reviewers.

Did you use AI tools to help write this code? _**NO**_

lib/GfxRenderer/GfxRenderer.h

@@ -110,8 +110,8 @@ class GfxRenderer {
                         EpdFontFamily::Style style = EpdFontFamily::REGULAR) const;
   void drawText(int fontId, int x, int y, const char* text, bool black = true,
                 EpdFontFamily::Style style = EpdFontFamily::REGULAR) const;
-  int getSpaceWidth(int fontId) const;
-  int getTextAdvanceX(int fontId, const char* text) const;
+  int getSpaceWidth(int fontId, EpdFontFamily::Style style = EpdFontFamily::REGULAR) const;
+  int getTextAdvanceX(int fontId, const char* text, EpdFontFamily::Style style) const;
   int getFontAscenderSize(int fontId) const;
   int getLineHeight(int fontId) const;
   std::string truncatedText(int fontId, const char* text, int maxWidth,