v0.2.2 : suggestions d'installation selon l'OS (scoop/winget/apt/dnf/pacman/apk/brew) + README remanie

src/installers/mod.rs

@@ -136,11 +136,24 @@ pub fn sh_inherit(
     Ok(())
 }
 
-/// Require a tool on the PATH, with an actionable error message.
+/// Require a tool on the PATH, with an actionable error message that
+/// includes the install command detected for the current OS.
 pub fn require_tool(runner: &dyn Runner, tool: &str, hint: &str) -> Result<PathBuf> {
-    runner
-        .which(tool)
-        .ok_or_else(|| anyhow!("'{tool}' not found on PATH — install it first ({hint})"))
+    if let Some(p) = runner.which(tool) {
+        return Ok(p);
+    }
+    let os = crate::toolchain::OsInfo::detect();
+    let mut msg = format!("'{tool}' not found on PATH — install it first ({hint})");
+    let cmds = crate::toolchain::install_commands(tool, &os);
+    if !cmds.is_empty() {
+        msg.push_str(&format!(
+            "
+  on {}: {}",
+            os.name,
+            cmds.join("  |  ")
+        ));
+    }
+    Err(anyhow!(msg))
 }
 
 /// Detect a binary's version via --version, then -V.