Implement text decoration styles (rebased)

[nicoburns]

Summary

Rebase of #510 onto latest main (couldn't push to the fork branch, so opening as a new PR).

Implements:

• text-decoration-style (solid / double / dotted / dashed / wavy, with geometry built explicitly for cross-renderer consistency; dashed gap selection mirrors Blink's SelectBestDashGap)
• text-decoration-thickness
• text-decoration-inset
• text-underline-offset
• text-underline-position
• overline support

Decorations are now accumulated per "decorating box" across a whole line (LineDecoration keyed by node id) and flushed once per line, so mixed font sizes within a box draw a single straight line rather than stepped per-run segments (matching Firefox). Overline/strikethrough placement uses the OS/2 usWinAscent (via a new read-fonts dependency), matching browser behaviour.

Rebase changes vs #510:

• resolved import conflicts in packages/blitz-paint/src/text.rs
• new commit "Adapt text-decoration code to NodeId newtype": node ids in the new decoration code (DecorationStackEntry, LineDecoration, path_scratch, stroke_text's inline_root_id) changed from usize to the NodeId newtype introduced on main

Verified with cargo check, clippy, fmt, and by rendering examples/assets/text-decoration.html with the screenshot example.

Link to Devin session: https://dioxus.staging.devinenterprise.com/sessions/1e40516b22b34e3d89abb619530f4b45
Requested by: @nicoburns

WPT results

18 newly passing, 11 newly failing (net +7).

Full diff (29 changed tests)

- Pass => Fail css/CSS2/text/painting-order-underline-001.xht
+ Fail => Pass css/css-text-decor/text-decoration-dotted-002.html
+ Fail => Pass css/css-text-decor/text-decoration-inset-001.html
+ Fail => Pass css/css-text-decor/text-decoration-inset-007.html
- Pass => Fail css/css-text-decor/text-decoration-inset-010.html
+ Fail => Pass css/css-text-decor/text-decoration-inset-015.html
+ Fail => Pass css/css-text-decor/text-decoration-inset-016.html
+ Fail => Pass css/css-text-decor/text-decoration-inset-024.html
- Pass => Fail css/css-text-decor/text-decoration-propagation-dynamic-001.html
+ Fail => Pass css/css-text-decor/text-decoration-propagation-shadow.html
+ Fail => Pass css/css-text-decor/text-decoration-style-multiple.html
- Pass => Fail css/css-text-decor/text-decoration-style-recalc.html
+ Fail => Pass css/css-text-decor/text-decoration-subelements-002.html
- Pass => Fail css/css-text-decor/text-decoration-subelements-004.html
+ Fail => Pass css/css-text-decor/text-decoration-thickness-001.html
+ Fail => Pass css/css-text-decor/text-decoration-thickness-calc.html
+ Fail => Pass css/css-text-decor/text-decoration-thickness-fixed.html
+ Fail => Pass css/css-text-decor/text-decoration-thickness-linethrough-001.html
+ Fail => Pass css/css-text-decor/text-decoration-thickness-scroll-001.html
+ Fail => Pass css/css-text-decor/text-decoration-thickness-single.html
+ Fail => Pass css/css-text-decor/text-underline-offset-001.html
- Pass => Fail css/css-text-decor/text-underline-offset-002.html
+ Fail => Pass css/css-text-decor/text-underline-offset-negative.html
+ Fail => Pass css/css-text-decor/text-underline-offset-scroll-001.html
- Pass => Fail css/css-text-decor/text-underline-offset-variable.html
- Pass => Fail css/css-text-decor/text-underline-offset-vertical-001.html
- Pass => Fail css/css-text-decor/text-underline-offset-vertical-002.html
- Pass => Fail css/css-text-decor/text-underline-offset-vertical-003.html
- Pass => Fail css/selectors/not-links.html

_{Generated by the WPT workflow.}

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