fix(tui): unify pending tool styling

[kitlangton]

Summary

• replace tilde-prefixed pending tool labels with the existing animated spinner
• render pending tool activity with the same muted treatment as grouped exploration
• preserve warning, failure, and hover colors

Testing

• bun typecheck in packages/tui
• bun run test test/cli/tui/inline-tool-wrap-snapshot.test.tsx
• repository pre-push typecheck (31 packages)
• exercised loading and failure transitions through opencode-drive recordings