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, 17 insertions, 0 deletions

diff --git a/src/action.rs b/src/action.rs
new file mode 100644
index 0000000..29ee079
--- /dev/null
+++ b/src/action.rs
@@ -0,0 +1,17 @@
+use serde::{Deserialize, Serialize};
+use strum::Display;
+
+/// Application-level events, distinct from [`crate::buffer::command::Command`],
+/// which is what key bindings name. `Action` is what the event loop routes;
+/// `Command` is what the editor executes.
+#[derive(Debug, Clone, PartialEq, Eq, Display, Serialize, Deserialize)]
+pub enum Action {
+    Tick,
+    Render,
+    Resize(u16, u16),
+    Suspend,
+    Resume,
+    Quit,
+    ClearScreen,
+    Error(String),
+}