add photo import: upload -> photoprism, fix desktop file dialog

- POST /api/import with native multipart parser (no new deps); stages files
  then delegates indexing+thumbnailing to PhotoPrism via `photoprism cp`
- pathways reflects new photos immediately via refresh()
- upload UI shown only in empty-library state
- nixos: PHOTOPRISM_READONLY=false; pathways service gets STAGING_ROOT and
  photoprism env; PATH includes /run/wrappers/bin so sudo is found
- fix: stage.setPointerCapture was swallowing the import label's click on
  desktop, preventing the native file dialog from opening

1 files changed, 15 insertions, 7 deletions

diff --git a/public/index.html b/public/index.html
index 549ca5d..0f44c6b 100644
--- a/public/index.html
+++ b/public/index.html
@@ -5,17 +5,25 @@
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <meta name="color-scheme" content="dark">
   <title>pathways</title>
-  <link rel="stylesheet" href="/app.css?v=26">
+  <link rel="stylesheet" href="/app.css?v=43">
 </head>
 <body>
   <main id="stage">
     <div id="world"></div>
+    <div id="import-state" hidden>
+      <h1>pathways<span class="dot">.</span></h1>
+      <p>your library is empty &mdash; add some photos to begin.</p>
+      <label id="import" for="file">
+        <svg viewBox="0 0 24 24" aria-hidden="true">
+          <path d="M12 16V4m0 0L7.5 8.5M12 4l4.5 4.5M4 16v2.5A1.5 1.5 0 0 0 5.5 20h13a1.5 1.5 0 0 0 1.5-1.5V16"/>
+        </svg>
+        <span>import photos</span>
+      </label>
+    </div>
   </main>
-  <div id="splash">
-    <h1>pathways<span class="dot">.</span></h1>
-    <p>four paths, one per direction. walk them.</p>
-    <button id="start">start</button>
-  </div>
-  <script src="/app.js?v=27"></script>
+  <input id="file" type="file" accept="image/jpeg,image/png,image/webp" multiple>
+  <div id="drop"><span>drop photos to import</span></div>
+  <div id="toast" role="status" aria-live="polite"></div>
+  <script src="/app.js?v=43"></script>
 </body>
 </html>