Fix login error feedback + load basecoat toast module

- inline error message on the login form (401 shows a visible French
  message, hidden again on submit)
- import basecoat-css/toast in BaseLayout: every showToast in the app
  was silently no-oping because the toast JS was never loaded

src/components/LoginForm.astro

@@ -27,6 +27,12 @@
                     required
                 />
             </div>
+            <p
+                id="login-error"
+                class="hidden text-sm m-0"
+                style="color: var(--destructive)"
+                role="alert"
+            ></p>
         </form>
     </section>
     <footer class="flex-col gap-2">
@@ -46,20 +52,18 @@
     const submitBtn = document.getElementById(
         "login-submit",
     ) as HTMLButtonElement;
-    const toaster = document.getElementById("toaster") as ToasterElement;
+    const errorEl = document.getElementById("login-error");
 
-    const showToast = (
-        category: "success" | "error",
-        title: string,
-        description: string,
-    ) => {
-        if (toaster?.toast) {
-            toaster.toast({ category, title, description });
+    const showError = (message: string) => {
+        if (errorEl) {
+            errorEl.textContent = message;
+            errorEl.classList.remove("hidden");
         }
     };
 
     form?.addEventListener("submit", async (e) => {
         e.preventDefault();
+        errorEl?.classList.add("hidden");
 
         const formData = new FormData(form as HTMLFormElement);
         const username = formData.get("username");
@@ -80,16 +84,12 @@
                 window.location.href = "/";
             } else {
                 const data = await res.json();
-                showToast(
-                    "error",
-                    "Erreur",
-                    data.error ?? "Identifiants incorrects",
-                );
+                showError(data.error ?? "Email ou mot de passe incorrect");
                 submitBtn.disabled = false;
                 submitBtn.innerHTML = originalText;
             }
         } catch {
-            showToast("error", "Erreur", "Erreur réseau");
+            showError("Erreur réseau, veuillez réessayer.");
             submitBtn.disabled = false;
             submitBtn.innerHTML = originalText;
         }

src/layouts/BaseLayout.astro

@@ -68,6 +68,7 @@ if (themePreference === "Dark") {
             import "basecoat-css/basecoat";
             import "basecoat-css/tabs";
             import "basecoat-css/dropdown-menu";
+            import "basecoat-css/toast";
         </script>
         <script is:inline>
             // Register the service worker so the browser offers "Install app"

src/pages/api/login.ts

@@ -69,9 +69,12 @@ export const POST: APIRoute = async ({ request, cookies }) => {
         });
     } catch (err) {
         console.error("Login failed:", err);
-        return new Response(JSON.stringify({ error: "Invalid credentials" }), {
+        return new Response(
+            JSON.stringify({ error: "Email ou mot de passe incorrect" }),
+            {
                 status: 401,
                 headers: { "Content-Type": "application/json" },
-        });
+            },
+        );
     }
 };