feat(react-styled): add uploads, file viewer, upload tool, and sharing views

[alikhere]

Summary

• Added dual-mode NavTabs — switches between home tabs (SPACES / IMPORT / CREATE / SETTINGS) and space tabs (UPLOADS / SHARE / UPLOAD / SETTINGS) when a space is selected
• Added SpaceUploadsView — uploads/blobs sub-tabs, table listing with Root CID and timestamp, pagination, and reload
• Added FileViewerView — Root CID, gateway URL, Shards rows, and remove confirmation dialog with cannot-be-undone warning
• Added UploadToolView — drag-and-drop file upload, type selector, progress bar, and wrap-in-directory option
• Added SharingToolView — contextual button labels (SHARE VIA EMAIL / SHARE VIA DID) and delegation URL display with copy button after DID share
• Exported all new components from packages/react-styled/src/index.ts
• Updated full-app-styled example to wire up space-mode navigation and all
  space workflows

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Related issue

Fixes #43
Part of #38

Screenshots

Test plan

• pnpm run ci passes
• Select a space → NavTabs switches to UPLOADS / SHARE / UPLOAD / SETTINGS
• Uploads list loads, RELOAD shows spinner, pagination works
• Click an upload → FileViewerView shows Root CID, URL, Shards (or "No shard
  data available")
• Click Remove → confirmation dialog appears with shards list and warning;
  Cancel closes it; Remove deletes and navigates back
• Upload tab → drag a file or click to browse, progress bar shows during
  upload, success state shows Root CID
• Share tab → type an email → button says SHARE VIA EMAIL; type a DID →
  button says SHARE VIA DID; DID share shows delegation URL with Copy button