Add link editing, AI re-description, and footer

Links can now be edited manually (title, summary, category,
manufacturer, tags) via an inline edit form, with a "KI neu
beschreiben lassen" action that re-fetches the URL and lets the AI
regenerate all fields. Editing recomputes the search embedding.

Also adds an app footer showing author, version, and hostname.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

app/templates/_link_card_edit.html

@@ -0,0 +1,54 @@
+<div class="panel link-card" id="link-{{ link.id }}">
+  <form hx-put="/links/{{ link.id }}" hx-target="#link-{{ link.id }}" hx-swap="outerHTML"
+        hx-disabled-elt="button">
+    <div class="muted" style="font-size:.8rem; overflow:hidden; text-overflow:ellipsis; white-space:nowrap; margin-bottom:8px;">
+      {{ link.url }}
+    </div>
+
+    <div class="field">
+      <label>Titel</label>
+      <input type="text" name="title" value="{{ link.title }}">
+    </div>
+
+    <div class="field">
+      <label>Zusammenfassung</label>
+      <textarea name="summary" rows="3" style="width:100%; background:var(--panel2); border:1px solid var(--border); color:var(--text); border-radius:8px; padding:10px 12px; font-size:.95rem; font-family:inherit;">{{ link.summary }}</textarea>
+    </div>
+
+    <div style="display:flex; gap:12px;">
+      <div class="field" style="flex:1;">
+        <label>Kategorie</label>
+        <input type="text" name="category" value="{{ link.category }}">
+      </div>
+      <div class="field" style="flex:1;">
+        <label>Hersteller / Quelle</label>
+        <input type="text" name="manufacturer" value="{{ link.manufacturer }}">
+      </div>
+    </div>
+
+    <div class="field">
+      <label>Tags (mit Komma getrennt)</label>
+      <input type="text" name="tags" value="{{ link.tag_list | join(', ') }}">
+    </div>
+
+    <div style="display:flex; justify-content:space-between; gap:8px; margin-top:4px;">
+      <div style="display:flex; gap:8px;">
+        <button type="submit">Speichern</button>
+        <button type="button" class="ghost"
+                hx-get="/links/{{ link.id }}/view"
+                hx-target="#link-{{ link.id }}"
+                hx-swap="outerHTML">Abbrechen</button>
+      </div>
+      {% if ai_enabled %}
+      <button type="button" class="ghost"
+              hx-post="/links/{{ link.id }}/reanalyze"
+              hx-target="#link-{{ link.id }}"
+              hx-swap="outerHTML"
+              hx-disabled-elt="this"
+              hx-confirm="Link erneut laden und von der KI neu beschreiben lassen? Bestehende Angaben werden dabei ersetzt.">
+        <span class="htmx-indicator">⏳</span> 🤖 KI neu beschreiben lassen
+      </button>
+      {% endif %}
+    </div>
+  </form>
+</div>