feat(react-styled): add NavTabs, SpaceList, SpaceCreatorView, ImportSpaceView, SpaceDetail, PlanGateView

[alikhere]

Summary

• Added NavTabs — pill tab bar for Spaces / Import / Create / Settings navigation
• Added SpaceList — space listing with Gravatar identicon avatars per space DID, empty state with create prompt
• Added SpaceDetail — space header with identicon, name, Public badge, DID, and breadcrumb back navigation
• Added SpaceCreatorView — space creation form wrapping headless SpaceCreator, with inline loading spinner and success state
• Added ImportSpaceView — import space via UCAN delegation file, shows agent DID with copy/email actions
• Added PlanGateView — subscription gate showing Starter / Lite / Business plan cards when account has no active plan; renders console immediately during plan check to avoid any loading flash
• Expanded examples/full-app-styled/src/App.tsx with full tab navigation and space workflows — ~70 lines, zero custom CSS, zero direct imports from @storacha/console-toolkit-react

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Related issue:

Fixes #41
Part of #38

Screenshots

Test plan

• pnpm run ci passes
• Login → console loads with NavTabs and SpaceList
• Clicking a space opens SpaceDetail with identicon and breadcrumb
• Create tab → form submits with spinner → opens created space
• Import tab → shows agent DID, file import works
• Login with account that has no subscription → plan selection page shown
• Login with subscribed account → console loads directly, no plan page