refactor: add markdown frontend

src/beaver_gateway/frontends/admin/templates/dashboard.html

@@ -134,6 +134,41 @@
       add one to <code>Gateway(frontends=[...])</code> to expose them over HTTP.
     </p>
     {% endif %}
+
+    {% if endpoints.markdown %}
+    <h3 class="ep-h3">Markdown — <code>POST /chat</code></h3>
+    <table class="ep-table" data-required-scope="messages">
+      <thead><tr><th>Vault</th><th>Default agent</th><th>URL</th><th class="ep-actions-th"></th></tr></thead>
+      <tbody>
+        <tr class="ep-row"
+            data-kind="markdown"
+            data-url="{{ endpoints.markdown.url }}"
+            data-sample-agent="{{ endpoints.markdown.sample_agent }}">
+          <td>
+            <code>{{ endpoints.markdown.vault_path }}</code>
+            <span class="ep-scope-warn" hidden>scope mismatch</span>
+            {% if endpoints.markdown.log_all_chats %}
+            <span class="pill">log_all_chats · {{ endpoints.markdown.logged_subdir }}/</span>
+            {% endif %}
+          </td>
+          <td>
+            {% if endpoints.markdown.default_agent %}
+              <code>{{ endpoints.markdown.default_agent }}</code>
+            {% else %}
+              <span class="muted">— (request must set <code>agent</code> or frontmatter)</span>
+            {% endif %}
+          </td>
+          <td><code class="ep-url">{{ endpoints.markdown.url }}</code></td>
+          <td class="ep-actions">
+            <button type="button" data-action="copy-url">Copy URL</button>
+            <button type="button" data-action="copy-curl">Copy curl</button>
+            <button type="button" data-action="toggle-curl" aria-expanded="false">▸ curl</button>
+          </td>
+        </tr>
+        <tr class="ep-curl-row" hidden><td colspan="4"><pre class="ep-curl"></pre></td></tr>
+      </tbody>
+    </table>
+    {% endif %}
     {% else %}
     <p class="muted">
       Nothing exposed yet — declare agents / MCPs and the matching frontends
@@ -284,6 +319,21 @@
         "  " + url,
       ].join("\n");
     }
+    if (kind === "markdown") {
+      const agent = row.getAttribute("data-sample-agent") || "";
+      const body = JSON.stringify({
+        filename: "example.md",
+        content: "### User:\n\nhello\n",
+        agent: agent,
+      });
+      return [
+        "curl \\",
+        "  -H " + escSh("Authorization: Bearer " + tok) + " \\",
+        "  -H 'content-type: application/json' \\",
+        "  -d " + escSh(body) + " \\",
+        "  " + url,
+      ].join("\n");
+    }
     if (kind === "mcp") {
       // Streamable-HTTP MCP wants `initialize` first — the response
       // carries the `Mcp-Session-Id` header you must echo back on