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.

README.md

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+# mcp-to-cli
+
+MCP servers advertise their tools as `(name, description, JSON Schema)`
+triples. `mcp-to-cli` turns each CLI-safe tool into a clap subcommand
+whose flags come from the schema's top-level properties, and turns
+parsed argv back into the `{property: value}` object the server
+expects.
+
+It is pure mapping: no I/O, no processes, no MCP protocol. `clap`,
+`serde_json`, and `thiserror` are the whole dependency list.
+
+## Use
+
+```rust
+use mcp_to_cli::{Payload, ToolInfo, args, command};
+
+fn main() {
+    let catalog = [ToolInfo {
+        name: "create_pull_request".into(),
+        description: "Create a new pull request".into(),
+        input_schema: serde_json::json!({
+            "type": "object",
+            "properties": {
+                "title": {"type": "string"},
+                "draft": {"type": "boolean", "default": false}
+            },
+            "required": ["title"]
+        }),
+    }];
+
+    let cmd = command("github", &catalog);
+    let matches = cmd
+        .try_get_matches_from(["github", "create_pull_request", "--title", "Ship it"])
+        .expect("argv parses");
+
+    match args(&cmd, &matches).expect("argv maps") {
+        Payload::Mapped(value) => println!("{value}"),  // {"title":"Ship it"}
+        Payload::Overridden(raw) => println!("{raw}"),  // the --json string, verbatim
+        Payload::Schema { tool } => println!("print the schema of {tool}"),
+        _ => unreachable!(),
+    }
+}
+```
+
+The mapping is conservative, with an escape hatch at every level of
+schema complexity:
+
+- enums become clap `possible_values`;
+- scalar arrays become repeatable flags;
+- every shape the flag form cannot express collapses to a
+  `--<property>_json` flag;
+- `--json` carries the whole argument object verbatim, for scripts;
+- schema defaults are never pre-filled: an omitted flag omits the key,
+  and the server stays the validator.
+
+Discovery rides along: a bare invocation answers with the tool list
+(`list_json`), and `--schema` asks for one tool's `input_schema`
+instead of calling it (`Payload::Schema`).
+
+## Examples
+
+```
+cargo run --example github      # the real GitHub create_pull_request schema
+cargo run --example blender     # a Blender MCP server's tools
+cargo run --example catalog     # every tool of a JSON catalog
+```
+
+`cargo test` drives the mapping matrix against vendored real schemas.