fix(web): improve coming soon badge styling on app store buttons

Integrate "Coming Soon" message into button text instead of using a
floating badge. Changes label from "Download on the" to "Coming soon to"
with coral accent color for better visual hierarchy.

Co-Authored-By: Claude Opus 4.5 <[e-mail]>

internal/web/templates/landing.html

···
         /* Placeholder state for app buttons */
         .app-button-placeholder {
             cursor: default;
-            opacity: 0.7;
+            background: transparent;
+            border-color: var(--color-text-muted);
+            color: var(--color-text-muted);
+        }
+
+        .app-button-placeholder svg {
+            opacity: 0.6;
         }
 
         .app-button-placeholder:hover {
             transform: none;
-            background: var(--color-deep);
-            border-color: var(--color-deep);
+            background: transparent;
+            border-color: var(--color-text-muted);
             box-shadow: none;
         }
 
···
             left: -100%;
         }
 
-        .coming-soon-badge {
-            position: absolute;
-            top: 6px;
-            right: 6px;
-            background: var(--color-coral);
-            color: var(--color-sand);
-            font-size: 0.6rem;
+        .app-button-placeholder .app-button-label {
+            color: var(--color-coral);
             font-weight: 700;
-            text-transform: uppercase;
-            letter-spacing: 0.05em;
-            padding: 3px 8px;
-            border-radius: 6px;
-            z-index: 2;
+            letter-spacing: 0.08em;
+        }
+
+        .app-button-placeholder .app-button-store {
+            color: var(--color-text-muted);
         }
 
         /* Built on AT Protocol badge - teal accent */
···
                         <path d="M18.71 19.5c-.83 1.24-1.71 2.45-3.05 2.47-1.34.03-1.77-.79-3.29-.79-1.53 0-2 .77-3.27.82-1.31.05-2.3-1.32-3.14-2.53C4.25 17 2.94 12.45 4.7 9.39c.87-1.52 2.43-2.48 4.12-2.51 1.28-.02 2.5.87 3.29.87.78 0 2.26-1.07 3.81-.91.65.03 2.47.26 3.64 1.98-.09.06-2.17 1.28-2.15 3.81.03 3.02 2.65 4.03 2.68 4.04-.03.07-.42 1.44-1.38 2.83M13 3.5c.73-.83 1.94-1.46 2.94-1.5.13 1.17-.34 2.35-1.04 3.19-.69.85-1.83 1.51-2.95 1.42-.15-1.15.41-2.35 1.05-3.11z"/>
                     </svg>
                     <span class="app-button-text">
-                        <span class="app-button-label">Download on the</span>
+                        <span class="app-button-label">Coming soon to</span>
                         <span class="app-button-store">App Store</span>
                     </span>
-                    <span class="coming-soon-badge">Coming Soon</span>
                 </div>
 
                 <div class="app-button app-button-placeholder" aria-label="Google Play - Coming Soon">
···
                         <path d="M3,20.5V3.5C3,2.91 3.34,2.39 3.84,2.15L13.69,12L3.84,21.85C3.34,21.6 3,21.09 3,20.5M16.81,15.12L6.05,21.34L14.54,12.85L16.81,15.12M20.16,10.81C20.5,11.08 20.75,11.5 20.75,12C20.75,12.5 20.5,12.92 20.16,13.19L17.89,14.5L15.39,12L17.89,9.5L20.16,10.81M6.05,2.66L16.81,8.88L14.54,11.15L6.05,2.66Z"/>
                     </svg>
                     <span class="app-button-text">
-                        <span class="app-button-label">Get it on</span>
+                        <span class="app-button-label">Coming soon to</span>
                         <span class="app-button-store">Google Play</span>
                     </span>
-                    <span class="coming-soon-badge">Coming Soon</span>
                 </div>
             </div>