Import mcp-to-cli from the rhema workspace

The crate maps MCP tool catalogs to clap commands and back, and has no
rhema dependencies — it was in-tree only because the workspace glob
reached it. Its own repository gives it its own release cadence and
its own crates.io token, scoped to this crate alone.

examples/github.rs

@@ -0,0 +1,44 @@
+//! A runnable demo of the required-argument story: the real GitHub
+//! `create_pull_request` schema (five required of nine properties), so
+//! the help output is what a real `github` command would look like.
+//! Same driver as the Blender example: bare prints help, argv maps.
+use mcp_to_cli::{Payload, ToolInfo, args, command};
+
+fn main() {
+    let schema = include_str!(concat!(
+        env!("CARGO_MANIFEST_DIR"),
+        "/tests/fixtures/create_pull_request.json"
+    ));
+    let catalog = [ToolInfo {
+        name: "create_pull_request".into(),
+        description: "Create a new pull request in a GitHub repository".into(),
+        input_schema: serde_json::from_str(schema).expect("fixture parses"),
+    }];
+    let mut cmd = command("github", &catalog);
+
+    let argv: Vec<String> = std::env::args().skip(1).collect();
+    if argv.is_empty() {
+        cmd.print_help().expect("help renders to stdout");
+        return;
+    }
+    let mut full = vec!["github"];
+    full.extend(argv.iter().map(String::as_str));
+    let matches = cmd
+        .clone()
+        .try_get_matches_from(full)
+        .unwrap_or_else(|e| e.exit());
+    match args(&cmd, &matches) {
+        Ok(Payload::Mapped(v)) => {
+            println!(
+                "{}",
+                serde_json::to_string_pretty(&v).expect("values render")
+            )
+        }
+        Ok(Payload::Overridden(raw)) => println!("--json override, verbatim: {raw}"),
+        Ok(_) => unreachable!("payload variants are the two above"),
+        Err(e) => {
+            eprintln!("{e}");
+            std::process::exit(2);
+        }
+    }
+}