Refactor web UI: CSS classes only, no inline styles; fix footer; add full lab1.zip

- Replace all inline style= with reusable CSS classes
- Add layout classes: page, page-header, page-main, page-footer
- Fix footer at bottom via flex column + flex:1 on main
- Remove jsessionid from static resource URLs
- Create lab1-full.zip with 30 variants from PDF metodichka
- All templates use CSS var classes for light/dark theme

web/src/main/resources/templates/login.html

@@ -1,29 +1,17 @@
 <!DOCTYPE html>
-<html lang="ru" xmlns:th="http://www.thymeleaf.org"
-      th:replace="~{fragments/base :: layout(~{::title}, ~{::#content})}">
+<html lang="ru" xmlns:th="http://www.thymeleaf.org" th:replace="~{fragments/base :: layout(~{::title}, ~{::#content})}">
 <head><title>Вход — LMS</title></head>
 <body>
 <div id="content">
-    <div style="max-width:28rem;margin:0 auto;">
-        <h1 style="margin:0 0 1.5rem;font-size:1.5rem;font-weight:600;">Вход</h1>
-
-        <div th:if="${error}" style="margin-bottom:1rem;padding:0.75rem 1rem;border-radius:0.5rem;font-size:0.875rem;background:#fef2f2;color:#991b1b;"
-             th:text="${error}"></div>
-
-        <div th:if="${!adminExists}" style="margin-bottom:1rem;padding:0.75rem 1rem;border-radius:0.5rem;font-size:0.875rem;background:#fef3c7;color:#92400e;">
-            Аккаунт администратора ещё не создан.
-            <a th:href="@{/setup}">Создать первый аккаунт</a>
+    <div class="container-sm">
+        <h1 class="page-title">Вход</h1>
+        <div th:if="${error}" class="alert alert-error" th:text="${error}"></div>
+        <div th:if="${!adminExists}" class="alert alert-warning">
+            Аккаунт администратора ещё не создан. <a th:href="@{/setup}">Создать первый аккаунт</a>
         </div>
-
-        <form class="card" style="padding:1.5rem;display:flex;flex-direction:column;gap:1rem;" th:action="@{/login}" method="post">
-            <div>
-                <label class="label" for="login">Логин</label>
-                <input class="input" id="login" name="login" th:value="${login}" autofocus required>
-            </div>
-            <div>
-                <label class="label" for="password">Пароль</label>
-                <input class="input" id="password" name="password" type="password" required>
-            </div>
+        <form class="card form-card form-stack" th:action="@{/login}" method="post">
+            <div><label class="label" for="login">Логин</label><input class="input" id="login" name="login" th:value="${login}" autofocus required></div>
+            <div><label class="label" for="password">Пароль</label><input class="input" id="password" name="password" type="password" required></div>
             <button class="btn btn-primary" type="submit">Войти</button>
         </form>
     </div>