prepare app for public app store distribution

- rebrand from 습관 트래커 to 해빗랩 across templates, manifest, service worker
- add HTTPS redirect middleware for reverse-proxied deployments
- add public landing page (/) and privacy policy page with real data
  handling disclosures
- add in-app account deletion (Apple review requirement)
- add Android TWA Digital Asset Links support (/.well-known/assetlinks.json)
- add SFTP deployment script for the Synology-hosted server

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

app/static/css/style.css

@@ -111,6 +111,16 @@ p {
   color: var(--color-text-muted);
 }
 
+.app-footer {
+  text-align: center;
+  padding: var(--space-4) 0 var(--space-2);
+  font-size: 13px;
+}
+
+.app-footer a {
+  color: var(--color-text-muted);
+}
+
 /* iOS 홈 화면 추가 안내 배너 */
 .ios-install-banner {
   display: none;
@@ -799,3 +809,154 @@ label {
 .wm-dash {
   color: var(--color-border);
 }
+
+/* 랜딩 페이지 (/) */
+.landing {
+  max-width: 480px;
+  margin: 0 auto;
+  padding: var(--space-4) var(--space-2) var(--space-4);
+  display: flex;
+  flex-direction: column;
+  gap: var(--space-4);
+}
+
+.landing-hero {
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  gap: var(--space-3);
+  text-align: center;
+}
+
+.landing-brand {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  font-size: 15px;
+  font-weight: 700;
+  color: var(--color-accent);
+  letter-spacing: -0.01em;
+}
+
+.landing-brand img {
+  width: 24px;
+  height: 24px;
+  border-radius: 6px;
+}
+
+.landing-hero h1 {
+  font-size: 32px;
+  font-weight: 700;
+  letter-spacing: -0.02em;
+  text-wrap: balance;
+  margin: 0;
+}
+
+.landing-tagline {
+  font-size: 16px;
+  color: var(--color-text-muted);
+  margin: 0;
+}
+
+/* 요일 스트릭 시연: 실제 습관 체크 인터랙션을 그대로 축소해 보여준다 */
+.landing-streak {
+  display: flex;
+  gap: 8px;
+}
+
+.landing-day {
+  width: 34px;
+  height: 34px;
+  border-radius: 999px;
+  border: 1px solid var(--color-border);
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  font-size: 12px;
+  color: var(--color-text-muted);
+  background: var(--color-surface);
+}
+
+.landing-day.done {
+  background: var(--color-accent);
+  border-color: var(--color-accent);
+  color: #fff;
+  opacity: 0;
+  animation: landing-day-in 0.35s ease-out forwards;
+}
+
+.landing-day.done svg {
+  width: 16px;
+  height: 16px;
+}
+
+.landing-day:nth-of-type(1).done { animation-delay: 0.1s; }
+.landing-day:nth-of-type(2).done { animation-delay: 0.25s; }
+.landing-day:nth-of-type(3).done { animation-delay: 0.4s; }
+.landing-day:nth-of-type(4).done { animation-delay: 0.55s; }
+.landing-day:nth-of-type(5).done { animation-delay: 0.7s; }
+
+@keyframes landing-day-in {
+  from {
+    opacity: 0;
+    transform: scale(0.6);
+  }
+  to {
+    opacity: 1;
+    transform: scale(1);
+  }
+}
+
+@media (prefers-reduced-motion: reduce) {
+  .landing-day.done {
+    opacity: 1;
+    animation: none;
+  }
+}
+
+.landing-copy {
+  font-size: 15.5px;
+  line-height: 1.75;
+  color: var(--color-text);
+  display: flex;
+  flex-direction: column;
+  gap: var(--space-2);
+}
+
+.landing-copy strong {
+  color: var(--color-accent);
+}
+
+.landing-features {
+  display: grid;
+  gap: var(--space-2);
+}
+
+.landing-feature {
+  display: flex;
+  align-items: center;
+  gap: var(--space-2);
+  padding: var(--space-2);
+  background: var(--color-surface);
+  border: 1px solid var(--color-border);
+  border-radius: var(--radius-card);
+}
+
+.landing-feature svg {
+  flex-shrink: 0;
+  width: 20px;
+  height: 20px;
+  color: var(--color-accent);
+}
+
+.landing-feature p {
+  margin: 0;
+  font-size: 14px;
+  color: var(--color-text);
+}
+
+.landing-feature p strong {
+  display: block;
+  font-size: 14.5px;
+  margin-bottom: 2px;
+}