v0.8.4: Documentation refresh + surface sizing fix

Docs pass covering v0.7.5–v0.8.3 module additions:
- STARLARK-REFERENCE: workspace module, permissions module, settings.has_capability()
- EXTENSION-GUIDE: capabilities manifest, vector(N) column, user_permissions,
  gate_permission, updated permissions list
- Tutorial reviewed for v0.7+ accuracy (no changes needed)

Surface sizing fix: .surface-inner converted to flex column layout so
the shell topbar and surface container share vertical space correctly.
All surface containers changed from height:100% to flex:1;min-height:0.
Eliminates 44px scroll cutoff on docs, admin, settings, and all
extension surfaces.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

server/pages/templates/base.html

@@ -29,7 +29,7 @@
     <style>
         body { margin: 0; background: var(--bg); color: var(--text); display: flex; flex-direction: column; height: 100vh; height: 100dvh; overflow: hidden; padding: env(safe-area-inset-top, 0) env(safe-area-inset-right, 0) env(safe-area-inset-bottom, 0) env(safe-area-inset-left, 0); }
         .surface { flex: 1; min-height: 0; overflow: hidden; }
-        .surface-inner { width: 100%; height: 100%; overflow: hidden; }
+        .surface-inner { width: 100%; height: 100%; overflow: hidden; display: flex; flex-direction: column; }
         .banner { flex-shrink: 0; }
     </style>
     <meta name="theme-color" content="#0e0e10" id="metaThemeColor">

server/pages/templates/surfaces/team-admin.html

@@ -6,7 +6,7 @@
 
 {{define "surface-team-admin"}}
 <div id="shell-topbar"></div>
-<div id="team-admin-mount" class="surface-team-admin" style="height:100%;overflow:hidden;">
+<div id="team-admin-mount" class="surface-team-admin" style="flex:1;min-height:0;overflow:hidden;">
     <div class="settings-placeholder" style="padding:40px;text-align:center;">Loading team admin&hellip;</div>
 </div>
 {{end}}

server/pages/templates/surfaces/welcome.html

@@ -4,7 +4,7 @@
 */}}
 
 {{define "surface-welcome"}}
-<div id="welcome-mount" style="display:flex;flex-direction:column;height:100%;"></div>
+<div id="welcome-mount" style="display:flex;flex-direction:column;flex:1;min-height:0;"></div>
 {{end}}
 
 {{define "scripts-welcome"}}