Improve backend error handling, fix lean logo on login screen

frontend/src/routes/+page.svelte

@@ -1,6 +1,5 @@
 <script lang="ts">
   import { api } from '$lib/api';
-  import Lean101Logo from '$lib/components/Lean101Logo.svelte';
   import { clientSession, sessionHydrated } from '$lib/session';
   import type { Mix, ProductCostBreakdown, RawMaterial } from '$lib/types';
   import packageInfo from '../../package.json';
@@ -28,8 +27,8 @@
   };
 
   let { data } = $props();
-  let email = $state('operator@example.com');
-  let password = $state('changeme');
+  let email = $state('');
+  let password = $state('');
   let isLoggingIn = $state(false);
   let loginError = $state('');
   let passwordInput: HTMLInputElement | null = null;
@@ -304,7 +303,7 @@
     <div class="auth-card auth-card-loading">
       <div class="auth-header">
         <div class="client-logo-block">
-          <Lean101Logo className="hero-logo" />
+          <img class="hero-login-logo" src="/lean101-login-logo.png" alt="Lean 101" />
           <div class="client-logo-copy">
             <p class="eyebrow">Client Workspace</p>
             <strong>Hunter Premium Produce</strong>
@@ -328,7 +327,7 @@
 
       <div class="auth-footer">
         <div class="lean-brand">
-          <Lean101Logo className="footer-logo" showTagline={false} />
+          <img class="footer-login-logo" src="/lean101-login-logo.png" alt="Lean 101" />
         </div>
         <div class="auth-meta">
           <span class="version-badge">
@@ -345,7 +344,7 @@
     <div class="auth-card auth-card-login">
       <div class="auth-header">
         <div class="client-logo-block">
-          <Lean101Logo className="hero-logo" />
+          <img class="hero-login-logo" src="/lean101-login-logo.png" alt="Lean 101" />
           <div class="client-logo-copy">
             <p class="eyebrow">Client Sign-In</p>
             <strong>Hunter Premium Produce</strong>
@@ -365,7 +364,7 @@
       <form class="signin-form auth-form" onsubmit={handleLogin}>
         <label class="field">
           <span>Email</span>
-          <input bind:value={email} type="email" autocomplete="username" placeholder="Email" />
+          <input bind:value={email} type="email" autocomplete="username" placeholder="Email" autofocus />
         </label>
 
         <label class="field field-password" class:is-invalid={Boolean(loginError)}>
@@ -390,7 +389,7 @@
 
       <div class="auth-footer">
         <div class="lean-brand">
-          <Lean101Logo className="footer-logo" showTagline={false} />
+          <img class="footer-login-logo" src="/lean101-login-logo.png" alt="Lean 101" />
         </div>
         <div class="auth-meta">
           <span class="version-badge">
@@ -798,20 +797,16 @@
     font-size: 0.88rem;
   }
 
-  :global(.hero-logo) {
+  .hero-login-logo {
     width: min(100%, 19rem);
+    height: auto;
+    display: block;
   }
 
-  :global(.hero-logo .logo-mark) {
-    width: 4.8rem;
-  }
-
-  :global(.hero-logo .logo-copy strong) {
-    font-size: clamp(2rem, 4.6vw, 3.2rem);
-  }
-
-  :global(.hero-logo .logo-copy small) {
-    font-size: 0.64rem;
+  .footer-login-logo {
+    width: 9.8rem;
+    height: auto;
+    display: block;
   }
 
   .auth-status-pill {
@@ -962,18 +957,6 @@
     align-items: center;
   }
 
-  :global(.footer-logo) {
-    width: 9.8rem;
-  }
-
-  :global(.footer-logo .logo-mark) {
-    width: 2rem;
-  }
-
-  :global(.footer-logo .logo-copy strong) {
-    font-size: 1.15rem;
-  }
-
   .auth-meta {
     display: grid;
     justify-items: end;