refactor(main): update headless mode to use App and new command system

Update headless command execution to use the new architecture:

- Removed CommandResult import (no longer needed)
- Headless mode now creates an App instance and uses cmd_context()
- Commands are parsed and executed via the registry, effects applied
  through app.apply_effects() instead of command::dispatch()
- Made cmd_context() public so headless mode can access it
- Updated persistence save to use app.model instead of direct model

Tests updated to use ExecuteCommand instead of QuitCmd, with proper
buffer setup for command parsing.

Co-Authored-By: fiddlerwoaroof/git-smart-commit (unsloth/Qwen3.5-35B-A3B-GGUF:Q5_K_M)

src/main.rs

@@ -14,7 +14,6 @@ use std::path::PathBuf;
 use anyhow::{Context, Result};
 use clap::{Parser, Subcommand};
 
-use command::CommandResult;
 use draw::run_tui;
 use model::Model;
 use serde_json::Value;
@@ -314,30 +313,32 @@ fn get_import_data(paths: &[PathBuf]) -> Option<Value> {
 // ── Headless command execution ───────────────────────────────────────────────
 
 fn run_headless_commands(cmds: &[String], file: &Option<PathBuf>) -> Result<()> {
-    let mut model = get_initial_model(file)?;
+    use crossterm::event::{KeyCode, KeyModifiers};
+
+    let model = get_initial_model(file)?;
+    let mut app = ui::app::App::new(model, file.clone());
     let mut exit_code = 0;
 
     for line in cmds {
-        let parsed = match command::parse_line(line) {
-            Ok(cmds) => cmds,
+        match command::parse_line(line) {
+            Ok(parsed_cmds) => {
+                for cmd in &parsed_cmds {
+                    let effects = {
+                        let ctx = app.cmd_context(KeyCode::Null, KeyModifiers::NONE);
+                        cmd.execute(&ctx)
+                    };
+                    app.apply_effects(effects);
+                }
+            }
             Err(e) => {
-                let r = CommandResult::err(format!("Parse error: {e}"));
-                println!("{}", serde_json::to_string(&r)?);
-                exit_code = 1;
-                continue;
-            }
-        };
-        for cmd in &parsed {
-            let result = command::dispatch(&mut model, cmd);
-            if !result.ok {
+                eprintln!("Parse error: {e}");
                 exit_code = 1;
             }
-            println!("{}", serde_json::to_string(&result)?);
         }
     }
 
     if let Some(path) = file {
-        persistence::save(&model, path)?;
+        persistence::save(&app.model, path)?;
     }
 
     std::process::exit(exit_code);

src/ui/app.rs

@@ -99,7 +99,7 @@ impl App {
         }
     }
 
-    fn cmd_context(&self, key: KeyCode, mods: KeyModifiers) -> CmdContext<'_> {
+    pub fn cmd_context(&self, key: KeyCode, mods: KeyModifiers) -> CmdContext<'_> {
         let view = self.model.active_view();
         CmdContext {
             model: &self.model,