✨➕♻️💩 cli, vanth, Cargo.toml, Cargo.lock: Add CLI framework and refactor vanth crate structure

- Added a new `vanth_cli` crate with `clap` command structure for `vanth fs open/save` commands.
- Removed `main.rs` from `vanth` crate as it is now a library without a binary target.
- Added `fs.rs` module and new structs `HashedValue`, `Value`, `Ty` with `Vanth` trait to support serialization.
- Updated `Cargo.toml` to include `clap` as a workspace dependency and added `vanth_cli` as a new crate.
- Added multiple dependencies (`anstream`, `anstyle`, `clap`, `heck`, etc.) in `Cargo.lock` to support the CLI.
- Created placeholder test files `tests/fs/mod.rs` and `tests/main.rs` in `vanth` crate for future use.
- Marked CLI command implementations with TODOs as functionality is not yet implemented.

crates/cli/src/cli.rs

@@ -0,0 +1,47 @@
+use clap::{Parser, Subcommand};
+
+#[derive(Parser, Debug)]
+#[command(name = "vanth")]
+#[command(about = "Vanth CLI tool")]
+pub struct Cli {
+    #[command(subcommand)]
+    pub command: Commands,
+}
+
+#[derive(Subcommand, Debug)]
+pub enum Commands {
+    #[command(about = "File system operations")]
+    Fs {
+        #[command(subcommand)]
+        command: FsCommands,
+    },
+}
+
+#[derive(Subcommand, Debug)]
+pub enum FsCommands {
+    #[command(about = "Read from path and print JSON to stdout")]
+    Open {
+        #[arg(help = "Path to read from")]
+        path: String,
+    },
+    #[command(about = "Take JSON from stdin and write to path")]
+    Save {
+        #[arg(help = "Path to write to")]
+        path: String,
+    },
+}
+
+pub fn execute(cli: Cli) {
+    match cli.command {
+        Commands::Fs { command } => match command {
+            FsCommands::Open { path } => {
+                // TODO: implement fs open functionality
+                println!("fs open: {}", path);
+            }
+            FsCommands::Save { path } => {
+                // TODO: implement fs save functionality
+                println!("fs save: {}", path);
+            }
+        },
+    }
+}