reject_disclaimer: delete sentinel file on decline

Added reject_disclaimer() to config.rs that removes the NOTALTERRA_LICENSE_ACCEPTED sentinel if it exists. Called from both decline paths in run_disclaimer() — the N/n key shortcut and Enter with No selected.

src/config.rs

@@ -50,6 +50,15 @@ pub fn accept_disclaimer() -> std::io::Result<()> {
     Ok(())
 }
 
+/// Remove the disclaimer sentinel if it exists.
+pub fn reject_disclaimer() -> std::io::Result<()> {
+    let p = sentinel_path();
+    if p.exists() {
+        std::fs::remove_file(p)?;
+    }
+    Ok(())
+}
+
 /// Path to the stale `config.ini` from v0.3.0 and earlier.
 pub fn stale_config_path() -> PathBuf {
     exe_dir().join("config.ini")

src/main.rs

@@ -349,6 +349,7 @@ fn run_disclaimer<B: Backend>(terminal: &mut Terminal<B>, app: &mut App) -> Resu
                 }
                 KeyCode::Char('n') | KeyCode::Char('N') => {
                     guard::log_action("LICENSE", "declined", "OK", &app.log_path)?;
+                    crate::config::reject_disclaimer()?;
                     return Ok(Some(false));
                 }
                 KeyCode::Esc => {
@@ -360,6 +361,8 @@ fn run_disclaimer<B: Backend>(terminal: &mut Terminal<B>, app: &mut App) -> Resu
                     guard::log_action("LICENSE", detail, "OK", &app.log_path)?;
                     if accepted {
                         crate::config::accept_disclaimer()?;
+                    } else {
+                        crate::config::reject_disclaimer()?;
                     }
                     return Ok(Some(accepted));
                 }