Simplify printer/ module for someone learning Rust

Drop reqwest, RPITIT+Send signature, and multi-variant error enum from the
teaching example so the only new idea per file is the trait override itself.
Real networking stays in adapters/, unaffected.

src/printer/klipper.rs

@@ -1,7 +1,3 @@
-use std::time::Duration;
-
-use tracing::info;
-
 use super::{Printer, PrinterBase, PrinterError};
 
 pub struct KlipperPrinter {
@@ -9,7 +5,7 @@ pub struct KlipperPrinter {
 }
 
 impl KlipperPrinter {
-    pub fn new(id: impl Into<String>, name: impl Into<String>, host: impl Into<String>) -> Self {
+    pub fn new(id: &str, name: &str, host: &str) -> Self {
         Self {
             base: PrinterBase { id: id.into(), name: name.into(), host: host.into() },
         }
@@ -21,22 +17,15 @@ impl Printer for KlipperPrinter {
         &self.base
     }
 
-    /// OVERRIDE: Moonraker's real-time feed is a WebSocket JSON-RPC channel
-    /// (see adapters::moonraker::run for that), but it also exposes a plain
-    /// REST endpoint. `connect()` here is a lightweight reachability probe
-    /// against that REST endpoint before the daemon opens the WS stream —
-    /// a third, again-completely-different notion of "connect".
+    /// OVERRIDE: a third, again-different body — Moonraker's real feed is a
+    /// WebSocket (see `adapters::moonraker`). This also shows the `Err`
+    /// path: an empty `host` fails immediately, same as any other vendor
+    /// would if it couldn't reach its printer.
     async fn connect(&mut self) -> Result<(), PrinterError> {
-        info!(printer = %self.base.id, host = %self.base.host, "probing Moonraker over HTTP");
-
-        reqwest::Client::new()
-            .get(format!("http://{}/printer/info", self.base.host))
-            .timeout(Duration::from_secs(5))
-            .send()
-            .await
-            .and_then(|resp| resp.error_for_status())
-            .map_err(|err| PrinterError::Connection(self.base.id.clone(), err.to_string()))?;
-
+        if self.base.host.is_empty() {
+            return Err(PrinterError(format!("{} has no host configured", self.base.name)));
+        }
+        println!("[{}] connecting over WebSocket (Moonraker)", self.base.name);
         Ok(())
     }
 }