feat: add import dashboard UI and functionality for CSV and Excel uploads

templates/imports/ui.html

@@ -0,0 +1,34 @@
+{% extends "base.html" %}
+{% from "partials/alerts.html" import toast %}
+
+{% block title %}Imports · CalMiner{% endblock %}
+
+{% block head_extra %}
+  <link rel="stylesheet" href="/static/css/imports.css" />
+{% endblock %}
+
+{% block content %}
+  <section class="page-header">
+    <div>
+      <h1>Data Imports</h1>
+      <p class="text-muted">Upload CSV or Excel files to preview and commit bulk updates.</p>
+    </div>
+  </section>
+
+  <section class="card" data-import-module>
+    <header class="card-header">
+      <h2>Upload Projects or Scenarios</h2>
+    </header>
+    <div class="card-body">
+  {% include "partials/import_upload.html" %}
+  {% include "partials/import_preview_table.html" %}
+
+      <div class="import-actions hidden" data-import-actions>
+        <button class="btn primary" data-import-commit disabled>Commit Import</button>
+        <button class="btn" data-import-cancel>Cancel</button>
+      </div>
+    </div>
+  </section>
+
+  {{ toast("import-toast", hidden=True) }}
+{% endblock %}