Implemented reliable cross-space switching in the web UI.
- Added a navigation coordinator that reacts only to changed URLs, preventing a session publication from reopening the previous URL's space.
- Routed picker selections through one action that opens the requested space, then replaces history with the neutral root URL carrying exactly one
spaceparameter. Failed opens retain the previous view and picker error state. - Added generation guards and stale-resource cleanup so overlapping opens cannot publish status, errors, recents, or polling state out of order.
- Added regression coverage for URL deduplication, successful and failed picker navigation, distinct sequential opens, and deferred out-of-order completion.
- Documented the new UI navigation boundary in the package source map.
Checks passed: pnpm --filter @radial/ui test (558 tests), pnpm --filter @radial/ui build, repository typecheck, and repository lint.