feat(gui): add create modals for issuers, policies, profiles, owners, teams, agent groups

Six pages were read-only viewers despite the API client having all
create functions wired up. Users deploying certctl had no way to create
CAs or other objects from the GUI — reported in GitHub issue.

- IssuersPage: 2-step create modal (type selection → config) for
  Local CA, ACME, step-ca, OpenSSL/Custom issuer types
- PoliciesPage: create modal with type, severity, JSON config, enabled
- ProfilesPage: create modal with name, description, max TTL, short-lived
- OwnersPage: create modal with name, email, team dropdown
- TeamsPage: create modal with name, description
- AgentGroupsPage: create modal with match criteria fields
- Layout.tsx: version v2.0.5 → v2.0.7
- cmd/server/main.go: version 0.1.0 → 2.0.7

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

web/src/components/Layout.tsx

@@ -69,7 +69,7 @@ export default function Layout() {
         </nav>
 
         <div className="px-5 py-3 border-t border-white/10 flex items-center justify-between">
-          <span className="text-[10px] text-brand-300/60 font-mono">v2.0.5</span>
+          <span className="text-[10px] text-brand-300/60 font-mono">v2.0.7</span>
           {authRequired && (
             <button
               onClick={logout}