fix(ui): ship the nav branding slot empty

It held the literal "phcode.dev", which was never a state the app meant to
show - just whatever the markup happened to contain until profile-menu.js
repainted it. Every user saw it for the first second of every start,
including the ones paying for a plan it was not naming.

Nothing belongs here until entitlements resolve, because the slot says
either "you could buy Pro" or "you have Pro" and neither is true yet. The
comment says so, so that it does not get helpfully filled back in.

Author: abose

src/index.html

@@ -922,10 +922,12 @@
                 <div id="newProject" class="new-project-btn btn-alt-quiet"></div>
             </div>
             <div>
-                <!-- placeholder only: profile-menu.js _updateBranding repaints this once entitlements
-                     resolve - localized "Get Phoenix Pro" for free users, plan name for pro users -->
+                <!-- Deliberately empty: profile-menu.js fills this once it knows what belongs
+                     here - the plan name for pro users, localized "Get Phoenix Pro" for free
+                     ones. Anything shipped here would be a guess made before entitlements
+                     resolve, and it would be shown to every user including the paying ones. -->
                 <a id="phcode-io-main-nav" href="https://phcode.dev/pricing?promo=FreeNavbar"
-                   target="_blank" rel="noopener">phcode.dev</a>
+                   target="_blank" rel="noopener"></a>
             </div>
             <div id="mainNavBarRight">
                 <div id="navBackButton" class="nav-back-btn btn-alt-quiet"><i class="fa-solid fa-arrow-left"></i></div>