feat: Phase 1 album selection with resume/start-over

Implements GET / listing Immich albums with resume badge, POST /select
creating TripState and redirecting to /triage; graceful error display
when Immich is unreachable.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

services/travel-memories/app/templates/phase1.html

@@ -0,0 +1,55 @@
+{% extends "base.html" %}
+{% block content %}
+<div class="p-6 max-w-5xl mx-auto">
+  <h1 class="text-2xl font-bold mb-4">Select Album</h1>
+
+  {% if error %}
+  <div class="alert alert-error mb-4">
+    <span>Cannot reach Immich: {{ error }}</span>
+    <a href="/" class="btn btn-sm">Retry</a>
+  </div>
+  {% endif %}
+
+  <form method="post" action="/select">
+    <div class="grid grid-cols-1 sm:grid-cols-2 lg:grid-cols-3 gap-4 mb-6">
+      {% for album in albums %}
+      <label class="album-card card bg-base-100 shadow cursor-pointer hover:shadow-lg transition"
+             data-album-id="{{ album.id }}">
+        <figure class="h-40 overflow-hidden">
+          <img src="/proxy/thumb/{{ album.albumThumbnailAssetId }}"
+               class="w-full h-full object-cover" alt="">
+        </figure>
+        <div class="card-body p-4">
+          <div class="flex items-start gap-2">
+            <input type="checkbox" name="album_ids[]" value="{{ album.id }}"
+                   class="checkbox checkbox-primary mt-1">
+            <div>
+              <p class="font-semibold">{{ album.albumName }}</p>
+              <p class="text-sm opacity-60">{{ album.assetCount }} photos</p>
+              {% if album.has_state %}
+              <span class="resume-badge badge badge-warning badge-sm mt-1">In progress</span>
+              {% endif %}
+            </div>
+          </div>
+        </div>
+      </label>
+      {% endfor %}
+    </div>
+
+    <div class="form-control mb-4 max-w-xs">
+      <label class="label"><span class="label-text">Grav trip slug</span></label>
+      <input id="grav-slug" type="text" name="grav_trip_slug" required
+             placeholder="central-asia-2023" class="input input-bordered">
+    </div>
+
+    <input type="hidden" name="start_over" id="start-over-flag" value="0">
+    <div class="flex gap-2">
+      <button type="submit" class="btn btn-primary">Start &rarr;</button>
+      <button type="button" class="btn btn-ghost btn-sm"
+              onclick="document.getElementById('start-over-flag').value='1'; this.closest('form').submit()">
+        Start over (discard progress)
+      </button>
+    </div>
+  </form>
+</div>
+{% endblock %}