Added foundational modules for core functionalities:

- Introduced `walk.rs` as a parallel directory walker for search operations.
- Implemented basic index handling in `commands/index.rs`.
- Created `utils/config.rs` for configuration management with placeholders for future enhancements.

src/commands/scan.rs

@@ -0,0 +1,53 @@
+use crate::cli::OutputFormat;
+use crate::utils::project::get_project_info;
+use std::path::Path;
+use crate::utils::config::Config;
+
+pub fn handle(
+    path: &str,
+    no_index: bool,
+    rebuild_index: bool,
+    format: OutputFormat,
+    high_only: bool,
+    database_dir: &Path,
+    config: &Config,
+) -> Result<(), Box<dyn std::error::Error>> {
+    let scan_path = Path::new(path).canonicalize()?;
+    let (project_name, db_path) = get_project_info(&scan_path, database_dir)?;
+
+    tracing::info!("Config: {:?}", config);
+    tracing::info!("Scanning project: {}", project_name);
+    tracing::info!("Scan path: {}", scan_path.display());
+
+    if no_index {
+        tracing::info!("Scanning without index...");
+        scan_filesystem(&scan_path)?;
+    } else {
+        if rebuild_index || !db_path.exists() {
+            tracing::info!("Building/updating index...");
+            crate::commands::index::build_index(&scan_path, &db_path)?;
+        }
+
+        tracing::info!("Using index: {}", db_path.display());
+        scan_with_index(&db_path)?;
+    }
+
+    tracing::info!("Output format: {:?}", format);
+    if high_only {
+        tracing::info!("Filtering: High severity only");
+    }
+
+    Ok(())
+}
+
+fn scan_filesystem(path: &Path) -> Result<(), Box<dyn std::error::Error>> {
+    // TODO: Implement direct filesystem scanning
+    tracing::info!("Direct filesystem scan of: {}", path.display());
+    Ok(())
+}
+
+fn scan_with_index(db_path: &Path) -> Result<(), Box<dyn std::error::Error>> {
+    // TODO: Implement index-based scanning
+    tracing::info!("Index-based scan using: {}", db_path.display());
+    Ok(())
+}