[refactor] remove backend and library modules, consolidating features into main crate

crates/polyscribe-core/src/error.rs

@@ -0,0 +1,39 @@
+// SPDX-License-Identifier: MIT
+
+use thiserror::Error;
+
+/// The common error type for the polyscribe core crate.
+/// Add more domain-specific variants as needed.
+#[derive(Debug, Error)]
+pub enum Error {
+    /// Wrapper for any boxed dynamic error. Useful as a temporary catch-all.
+    #[error("anyhow error: {0}")]
+    Anyhow(#[from] anyhow::Error),
+
+    /// IO-related error.
+    #[error("io error: {0}")]
+    Io(#[from] std::io::Error),
+
+    /// UTF-8 conversion error.
+    #[error("utf8 error: {0}")]
+    Utf8(#[from] std::string::FromUtf8Error),
+
+    /// Environment variable error.
+    #[error("env var error: {0}")]
+    Var(#[from] std::env::VarError),
+
+    /// TOML de serialization error.
+    #[error("toml de error: {0}")]
+    TomlDe(#[from] toml::de::Error),
+
+    /// Configuration parsing error.
+    #[error("configuration error: {0}")]
+    Config(String),
+
+    /// Placeholder for not-yet-implemented backends or features.
+    #[error("unimplemented: {0}")]
+    Unimplemented(&'static str),
+}
+
+/// Convenient result alias for the polyscribe core crate.
+pub type Result<T> = std::result::Result<T, Error>;