Add error handling with NyxError and refactor console output formatting

- Introduced `NyxError` and `NyxResult` for unified error handling across modules.
- Refactored `scan.rs`, `index.rs`, and `walk.rs` with improved error management and consistent formatting.
- Replaced existing error handling in `database.rs` with `NyxResult`.
- Improved database maintenance by integrating `vacuum` and `clear` methods into workflows.
- Added `dashmap` for efficient parallel diagnostics result aggregation in `scan_with_index_parallel`.
- Enhanced readability and formatting of console outputs in multiple modules.

src/utils/project.rs

@@ -1,27 +1,30 @@
 use std::path::{Path, PathBuf};
+use crate::errors::{NyxError, NyxResult};
 
+/// Determine `<project-name, path/to/<project>.sqlite>`.
 pub fn get_project_info(
-    project_path: &Path,
-    config_dir: &Path,
-) -> Result<(String, PathBuf), Box<dyn std::error::Error>> { 
+  project_path: &Path,
+  config_dir:   &Path,
+) -> NyxResult<(String, PathBuf)> {
+
   let project_name = project_path
     .file_name()
-    .and_then(|name| name.to_str())
-    .ok_or("Unable to determine project name")?;
-  
+    .and_then(|n| n.to_str())
+    .ok_or_else(|| NyxError::Other("Unable to determine project name".into()))?;
+
   let db_name = sanitize_project_name(project_name);
   let db_path = config_dir.join(format!("{}.sqlite", db_name));
-  
-  Ok((project_name.to_string(), db_path))
+
+  Ok((project_name.to_owned(), db_path))
 }
 
-pub fn sanitize_project_name(name: &str) -> String { 
+pub fn sanitize_project_name(name: &str) -> String {
   name.to_lowercase()
     .chars()
-    .map(|c| match c { 
-      ' ' | '\t' | '\n' | '\r' => '_', 
-      c if c.is_alphanumeric() || c == '_' || c == '-' => c, 
-      _ => '_' 
+    .map(|c| match c {
+      ' ' | '\t' | '\n' | '\r'               => '_',
+      c if c.is_alphanumeric() || c == '_' || c == '-' => c,
+      _                                      => '_',
     })
     .collect::<String>()
     .split('_')