fix: expand tilde (~) in config file paths to home directory

Applies to dir, import_data_file, and all server certificate/secret file
paths. Uses existing dirs crate for home directory resolution.

src/config.rs

@@ -4,7 +4,7 @@ use dirs;
 use log::{debug, error};
 use serde::{Deserialize, Serialize};
 use std::fs;
-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
 
 #[derive(Debug, Clone, Serialize, Deserialize, Default)]
 #[serde(rename_all = "lowercase")]
@@ -542,6 +542,25 @@ impl Settings {
                 settings.export_filename_format = args.item.export_filename_format.clone();
                 settings.import_data_file = args.item.import_data_file.clone();
 
+                // Expand ~ in all path fields
+                settings.dir = Settings::expand_tilde(&settings.dir);
+                settings.import_data_file = settings
+                    .import_data_file
+                    .as_ref()
+                    .map(|p| Settings::expand_tilde(p));
+                if let Some(ref mut server) = settings.server {
+                    server.password_file = server
+                        .password_file
+                        .as_ref()
+                        .map(|p| Settings::expand_tilde(p));
+                    server.jwt_secret_file = server
+                        .jwt_secret_file
+                        .as_ref()
+                        .map(|p| Settings::expand_tilde(p));
+                    server.cert_file = server.cert_file.as_ref().map(|p| Settings::expand_tilde(p));
+                    server.key_file = server.key_file.as_ref().map(|p| Settings::expand_tilde(p));
+                }
+
                 debug!("CONFIG: Final settings: {settings:?}");
                 Ok(settings)
             }
@@ -562,6 +581,24 @@ impl Settings {
         Ok(path)
     }
 
+    /// Expand a leading `~` in a path to the user's home directory.
+    ///
+    /// Returns the path unchanged if it doesn't start with `~` or if the
+    /// home directory cannot be determined.
+    fn expand_tilde(path: &Path) -> PathBuf {
+        let path_str = path.to_string_lossy();
+        if let Some(rest) = path_str.strip_prefix("~/") {
+            if let Some(home) = dirs::home_dir() {
+                return home.join(rest);
+            }
+        } else if path_str == "~" {
+            if let Some(home) = dirs::home_dir() {
+                return home;
+            }
+        }
+        path.to_path_buf()
+    }
+
     /// Get server password from password_file or directly from config if configured
     pub fn get_server_password(&self) -> Result<Option<String>> {
         if let Some(server) = &self.server {
@@ -753,3 +790,35 @@ impl Settings {
             .collect()
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::path::Path;
+
+    #[test]
+    fn test_expand_tilde_with_slash() {
+        let home = dirs::home_dir().unwrap();
+        let result = Settings::expand_tilde(Path::new("~/foo/bar"));
+        assert_eq!(result, home.join("foo/bar"));
+    }
+
+    #[test]
+    fn test_expand_tilde_bare() {
+        let home = dirs::home_dir().unwrap();
+        let result = Settings::expand_tilde(Path::new("~"));
+        assert_eq!(result, home);
+    }
+
+    #[test]
+    fn test_expand_tilde_absolute() {
+        let result = Settings::expand_tilde(Path::new("/etc/keep"));
+        assert_eq!(result, PathBuf::from("/etc/keep"));
+    }
+
+    #[test]
+    fn test_expand_tilde_relative() {
+        let result = Settings::expand_tilde(Path::new("foo/bar"));
+        assert_eq!(result, PathBuf::from("foo/bar"));
+    }
+}