chore: beta release v0.5.0-beta

- Bump version to 0.5.0-beta
- Add Apache-2.0 LICENSE (official text) + NOTICE
- Add Docker support: multi-stage Dockerfile + docker-compose
  * non-root user, tini PID 1, gunicorn + uvicorn workers
  * healthcheck, OCI labels, persistent /data volume
- Add GitHub Actions CI (lint/import-check + Docker smoke-test)
- Backend polish:
  * modern lifespan handler (replaces deprecated on_event)
  * explicit sort validation (400 instead of 500)
  * title min_length=1 schema validation
  * configurable data dir + http timeout via env
  * avg_rating helper extracted (DRY)
- Frontend polish:
  * beta badge in title, footer with live version
  * loading spinner on initial fetch
  * updated README, badges, config table, roadmap

app/static/css/style.css

@@ -96,6 +96,22 @@ a { color: var(--accent-2); text-decoration: none; }
 }
 .brand-text p { margin: 2px 0 0; color: var(--text-dim); font-size: 14px; }
 
+.version-badge {
+  display: inline-block;
+  margin-left: 8px;
+  vertical-align: middle;
+  font-size: 10px;
+  font-weight: 800;
+  letter-spacing: .1em;
+  text-transform: uppercase;
+  padding: 3px 7px;
+  border-radius: 999px;
+  background: linear-gradient(135deg, rgba(245,158,11,.25), rgba(239,68,68,.25));
+  color: #fbbf24;
+  border: 1px solid rgba(245,158,11,.4);
+  -webkit-text-fill-color: #fbbf24;
+}
+
 .hero-search {
   display: flex; gap: 10px; flex-wrap: wrap;
   align-items: center;
@@ -224,6 +240,22 @@ a { color: var(--accent-2); text-decoration: none; }
   margin-top: 14px;
 }
 
+.grid-loading {
+  grid-column: 1 / -1;
+  display: flex; align-items: center; justify-content: center;
+  gap: 12px;
+  padding: 60px 20px;
+  color: var(--text-dim);
+}
+.spinner {
+  width: 22px; height: 22px;
+  border: 2px solid var(--border);
+  border-top-color: var(--accent);
+  border-radius: 50%;
+  animation: spin .8s linear infinite;
+}
+@keyframes spin { to { transform: rotate(360deg); } }
+
 .card {
   background: var(--bg-elev);
   border: 1px solid var(--border);
@@ -541,3 +573,16 @@ body.kind-series .row[data-when="series"] { display: flex; }
   .status-tabs { padding: 4px 12px 0; }
   .tab { padding: 10px 10px; font-size: 13px; }
 }
+
+/* ===================== Footer ===================== */
+.footer {
+  max-width: var(--container);
+  margin: 0 auto;
+  padding: 24px 24px 40px;
+  display: flex; justify-content: space-between; align-items: center;
+  color: var(--text-muted);
+  font-size: 12px;
+  border-top: 1px solid var(--border);
+  margin-top: 40px;
+}
+.footer span:last-child { color: var(--text-dim); }