Merge branch 'buffer-implementation'HEADmain

Establishes the first working baseline: moji <file> opens a file into a
ropey rope and edits it with Helix selection-first modal editing, under a
DO-178C DAL-C requirements and traceability process.

Prior to this, main tracked four files and src/main.rs was still
println!("Hello, world!") — there was no buildable state to build on.

Verified on a fresh clone of the branch with no untracked files:
cargo build; clippy --all-targets -D warnings clean; 294 tests passing;
scripts/check-trace.sh reports 98/98 requirements traced in both
directions.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

1 files changed, 54 insertions, 0 deletions

diff --git a/src/cli.rs b/src/cli.rs
new file mode 100644
index 0000000..9b50bcb
--- /dev/null
+++ b/src/cli.rs
@@ -0,0 +1,54 @@
+use std::path::PathBuf;
+
+use clap::Parser;
+
+use crate::config::{get_config_dir, get_data_dir};
+
+#[derive(Parser, Debug)]
+#[command(author, version = version(), about)]
+pub struct Cli {
+    /// File to edit. A path that does not exist is created on write.
+    // MJB-LLR-111, MJB-LLR-112
+    #[arg(value_name = "FILE")]
+    pub file: Option<PathBuf>,
+
+    /// Tick rate, i.e. number of ticks per second
+    #[arg(short, long, value_name = "FLOAT", default_value_t = 4.0)]
+    pub tick_rate: f64,
+
+    /// Frame rate, i.e. number of frames per second
+    #[arg(short, long, value_name = "FLOAT", default_value_t = 60.0)]
+    pub frame_rate: f64,
+}
+
+const VERSION_MESSAGE: &str = concat!(
+    env!("CARGO_PKG_VERSION"),
+    "-",
+    env!("VERGEN_GIT_DESCRIBE"),
+    " (",
+    env!("VERGEN_BUILD_DATE"),
+    ")"
+);
+
+/// The `origin` remote of the checkout this binary was built from, emitted by
+/// `build.rs`.
+const GIT_REMOTE_URL: &str = env!("VERGEN_GIT_REMOTE_URL");
+
+pub fn version() -> String {
+    let author = clap::crate_authors!();
+
+    // let current_exe_path = PathBuf::from(clap::crate_name!()).display().to_string();
+    let config_dir_path = get_config_dir().display().to_string();
+    let data_dir_path = get_data_dir().display().to_string();
+
+    format!(
+        "\
+{VERSION_MESSAGE}
+
+Authors: {author}
+
+Repository: {GIT_REMOTE_URL}
+Config directory: {config_dir_path}
+Data directory: {data_dir_path}"
+    )
+}