…in names

…tively

- Created separate crates: rheo-core, rheo-html, rheo-pdf, rheo-epub, rheo-cli
- rheo-core provides shared utilities, config, diagnostics, and plugin traits
- Each format plugin implements FormatPlugin trait for format-specific compilation
- CLI crate provides compile, watch, clean, and init commands
- Clean build with no warnings

…PluginContext

Both per-format and global

…→HTML dependency

…ted Typst code

…HashMap

…files