feat: add app code

- journal domain package
- httpserver package
- html templates
- main.go in root dir

templates/edit-entry.html

@@ -0,0 +1,61 @@
+{{ template "layout.html" . }}
+
+{{ define "title" }}Edit entry: {{ .Title }}{{ end }}
+
+{{ define "content" }}
+<style>
+  form {
+    display: flex;
+    flex-direction: column;
+    /* max-width: 600px; */
+    margin: 0 auto;
+  }
+  form input,
+  form textarea {
+    font-size: 1rem;
+    width: calc(100% - 1rem);
+  }
+  form input[type="date"] {
+    padding: 0.5rem;
+    margin-bottom: 1rem;
+    border-radius: 0.5rem;
+    border: 1px solid #ccc;
+  }
+  form input[type="text"] {
+    padding: 0.5rem;
+    margin-bottom: 1rem;
+    border-radius: 0.5rem;
+    border: 1px solid #ccc;
+  }
+  form textarea {
+    padding: 0.5rem;
+    margin-bottom: 1rem;
+    border-radius: 0.5rem;
+    border: 1px solid #ccc;
+    resize: none;
+    height: 24rem;
+  }
+</style>
+<script>
+  function editEntry(event) {
+    event.preventDefault();
+    document.getElementById('edit-entry').submit();
+  }
+</script>
+<main class="container">
+  <h1>Edit entry: {{ .Title }}</h1>
+  <hr />
+  <p>
+    [<a href="/entry/{{ .ID }}">Back to entry</a>]
+  </p>
+  <hr />
+  <form id="edit-entry" action="/entry/{{ .ID }}/edit" method="POST">
+    <input type="text" name="title" placeholder="Title" value="{{ .Title }}" required>
+    <input type="date" name="date" value="{{ .FormattedDate }}" required>
+    <textarea name="content" placeholder="Content" rows="12" required>{{ .Content }}</textarea>
+    <div>
+      [<a href="#" onclick="editEntry(event)">Save</a>]
+    </div>
+  </form>
+</main>
+{{ end }}