feat: paragraph alignment, attachment & spacing; CharFormat width/tracking/oblique; pnpm 10 + CI

[mlightcad]

Summary

• Extends the MTEXT editor viewer with ribbon-style paragraph horizontal alignment, nine-point attachment, and line spacing controls, wired through MTextData and renderer constants.
• Expands CharFormat and format merging so width factor, tracking, oblique angle, and paragraph alignment round-trip with document styles and MTEXT serialization.
• Preserves existing paragraph layout fields (indent, margins, tabs) when applying character-level style updates by merging into toDocumentStyle(..., existing?).
• Bumps @mlightcad/mtext-renderer peer to ^0.10.13 and package version to 0.2.8; refreshes lockfile.
• Upgrades the monorepo to pnpm 10.33.4 (packageManager, engines.pnpm), adds pnpm.onlyBuiltDependencies, updates CI (pnpm/action-setup@v4), and documents the change in AGENTS.md.
• Adds a Vitest covering paragraph alignment codes in built MTEXT and parser PROPERTIES_CHANGED behavior.
• Removes a stray console.log from editor snapshot code.