Release 0.2.2: embedded manifests, catalog paths and typed errors

[SDA-31]

Release 0.2.2 with named embedded manifest constants, one package-relative catalog input and typed configuration/build errors.

Selective embedding uses embed_manifest! { pub const HUD = presentation::Hud; }. Generated catalog types no longer share names with callable embedding helpers; ordinary catalog imports and resource aliases remain usable. Cargo metadata contains only catalog; Settings::asset_root and generated ASSET_ROOT are removed, and CATALOG_PATH replaces CATALOG_ASSET_PATH. Unknown configuration fields are ignored while known values remain validated.

Configuration parsers return ConfigError; explicit generation returns BuildError, retaining original causes and filesystem context. ManifestError uses typed configuration and virtual-origin variants. The standard build() -> ExitCode setup, typed accessors and catalog-constructor signatures remain unchanged. Error implementations live in separate files under a private errors module with compatible crate-root re-exports.

The version includes a categorized changelog, migration from 0.2.1, aligned dependency snippets and updated examples. Temporary maintainer notes, benchmarks and proprietary game content are excluded.

Validation: green CI on Linux, Windows and macOS, including Rust 1.95; generator and engine-free consumer tests, doctests, unoptimized embedding exclusion, incremental generation, Clippy with warnings denied, Rustdoc, formatting, macro-only/manifest-only dependency isolation and distributable archive verification. Publication is performed separately after merged-revision and registry-backed verification.