Text styling modifiers

[colemancda]

First parity tier: text styling. Adds the text-attribute modifiers and applies them as parameters of the Compose Text composable (they describe the text, not the layout Modifier chain, so they are read off a Text node's modifier list rather than folded).

New modifiers

• .font(_:) — named styles (.largeTitle….caption2, resolved to point sizes by the interpreter) and .system(size:weight:)
• .foregroundColor(_:) / .foregroundStyle(_:)
• .bold() / .fontWeight(_:)
• .italic()
• .lineLimit(_:)
• .multilineTextAlignment(_:)

Multiple text modifiers compose on one Text; later (innermost) entries win for scalar attributes, and layout modifiers in the same chain still apply normally.

Verification

• swift test — 6 new emission tests, 35 total passing
• Emulator: Text playground shows font sizes (largeTitle→caption, headline correctly semibold), weight/italic/heavy, colors, composed title + bold + green, and lineLimit(2) truncation vs. full multiline

Deferred

Container-level font/color environment propagation (styling only applies when set directly on a Text). Tracked for a later tier.