feat: initialize codebase-to-prompt project with core functionality

- Added Cargo.toml for project dependencies and metadata.
- Implemented main library logic in src/lib.rs to process files in a directory.
- Introduced configuration struct to manage input parameters.
- Added command-line argument parsing in src/main.rs using clap.
- Implemented output formatting options (Markdown, Text, Console).
- Integrated tracing for logging and error handling.
- Added support for including/excluding file types and respecting .gitignore.

src/main.rs

@@ -0,0 +1,64 @@
+use anyhow::Result;
+use clap::Parser;
+use codebase_to_prompt::Format;
+use std::path::PathBuf;
+use tracing::level_filters::LevelFilter;
+use tracing_subscriber::FmtSubscriber;
+
+#[derive(Parser, Debug)]
+#[command(author, version, about, long_about = None)]
+struct Args {
+    #[arg(default_value = ".")]
+    directory: PathBuf,
+
+    #[arg(short, long)]
+    output: Option<PathBuf>,
+
+    #[arg(short, long, use_value_delimiter = true, default_value = "")]
+    include: Vec<String>,
+
+    #[arg(short, long, use_value_delimiter = true, default_value = "")]
+    exclude: Vec<String>,
+
+    #[arg(long, value_enum, default_value_t = Format::Console)]
+    format: Format,
+
+    #[arg(long)]
+    append_date: bool,
+
+    #[arg(long)]
+    append_git_hash: bool,
+
+    #[arg(long)]
+    line_numbers: bool,
+
+    #[arg(long)]
+    ignore_hidden: bool,
+
+    #[arg(long, default_value_t = true)]
+    respect_gitignore: bool,
+}
+
+fn main() -> Result<()> {
+    let subscriber = FmtSubscriber::builder()
+        .with_max_level(LevelFilter::INFO)
+        .finish();
+    tracing::subscriber::set_global_default(subscriber).expect("setting default subscriber failed");
+
+    let args = Args::parse();
+
+    let config = codebase_to_prompt::Config {
+        directory: args.directory,
+        output: args.output,
+        include: args.include,
+        exclude: args.exclude,
+        format: args.format,
+        append_date: args.append_date,
+        append_git_hash: args.append_git_hash,
+        line_numbers: args.line_numbers,
+        ignore_hidden: args.ignore_hidden,
+        respect_gitignore: args.respect_gitignore,
+    };
+
+    codebase_to_prompt::run(config)
+}