feat: add fallback to file command when magic crate is disabled

Co-authored-by: aider (openai/andrew/openrouter/sonoma-sky-alpha) <aider@aider.chat>

src/meta_plugin/mod.rs

@@ -34,6 +34,9 @@ pub use shell_pid::ShellPidMetaPlugin;
 pub use keep_pid::KeepPidMetaPlugin;
 pub use env::EnvMetaPlugin;
 
+#[cfg(not(feature = "magic"))]
+pub use magic_file::FallbackMagicFileMetaPlugin as MagicFileMetaPlugin;
+
 type PluginConstructor = fn(Option<HashMap<String, serde_yaml::Value>>, Option<HashMap<String, serde_yaml::Value>>) -> Box<dyn MetaPlugin>;
 
 /// Represents metadata to be stored.
@@ -191,7 +194,6 @@ impl MetaPlugin for BaseMetaPlugin {
 #[derive(Debug, Eq, PartialEq, Clone, Hash, strum::EnumIter, strum::Display, strum::EnumString, Serialize, Deserialize)]
 #[strum(serialize_all = "snake_case", ascii_case_insensitive)]
 pub enum MetaPluginType {
-    #[cfg(feature = "magic")]
     MagicFile,
     Cwd,
     Text,