#### Brief overview of PR changes/additions
Adds support for additional MXP 1.0 HTML tags:
- **HR tag**: Renders a horizontal rule (line of dashes) spanning the
full console width
- **H1-H6, SMALL, TT tags**: Recognized and parsed without visual
styling changes
The HR tag automatically adjusts to each profile's wrap width setting
and properly handles line breaks, ensuring text before and after the
horizontal rule appears correctly.
#### Motivation for adding to Mudlet
Improves MXP compliance with the MXP 1.0 specification, allowing MUDs to
use more HTML formatting tags. The HR tag provides a visual separator
for content sections, useful for menus, help text, and scene
transitions.
#### Other info (issues closed, discussion etc)
Closes#8481
**Implementation notes:**
- Variable font sizes (H1-H6, SMALL) are not feasible due to Mudlet's
fixed-width rendering architecture
- Tags are recognized to prevent them from displaying as raw text
- HR width respects the profile's word-wrap setting (`mWrapAt`)
- New `TMxpHRTagHandler` injects text through the MXP processing
pipeline to maintain proper line buffering
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Co-authored-by: Vadim Peretokin <vperetokin@hey.com>
