Feat: WIP terse code documentation

crates/project/src/file.rs

@@ -1,3 +1,5 @@
+//! JSON-based project file persistence with versioned format.
+
 use std::fs;
 use std::io;
 use std::path::{Path, PathBuf};
@@ -7,9 +9,9 @@ use serde::{Deserialize, Serialize};
 use crate::project::{Bank, Project};
 
 const VERSION: u8 = 1;
-pub const EXTENSION: &str = "cagire";
+const EXTENSION: &str = "cagire";
 
-pub fn ensure_extension(path: &Path) -> PathBuf {
+fn ensure_extension(path: &Path) -> PathBuf {
     if path.extension().map(|e| e == EXTENSION).unwrap_or(false) {
         path.to_path_buf()
     } else {
@@ -62,6 +64,7 @@ impl From<ProjectFile> for Project {
     }
 }
 
+/// Error returned by project save/load operations.
 #[derive(Debug)]
 pub enum FileError {
     Io(io::Error),
@@ -91,6 +94,7 @@ impl From<serde_json::Error> for FileError {
     }
 }
 
+/// Write a project to disk as pretty-printed JSON, returning the final path.
 pub fn save(project: &Project, path: &Path) -> Result<PathBuf, FileError> {
     let path = ensure_extension(path);
     let file = ProjectFile::from(project);
@@ -99,11 +103,13 @@ pub fn save(project: &Project, path: &Path) -> Result<PathBuf, FileError> {
     Ok(path)
 }
 
+/// Read a project from a `.cagire` file on disk.
 pub fn load(path: &Path) -> Result<Project, FileError> {
     let json = fs::read_to_string(path)?;
     load_str(&json)
 }
 
+/// Parse a project from a JSON string.
 pub fn load_str(json: &str) -> Result<Project, FileError> {
     let file: ProjectFile = serde_json::from_str(json)?;
     if file.version > VERSION {