* feat: cross-repo issues view with multi-repo selection
- Add multi-repo selection via RepoMultiCombobox with persisted defaultRepoSelection setting (null = sticky-all)
- Stamp repoId on GitHubWorkItem at the renderer fetch boundary; merge items from all selected repos with per-repo failure tracking
- Extract task-query helpers (tokenize/strip/parseTaskQuery) to src/shared and add unit tests
- Refactor NewWorkspacePage row to <div role=button> to allow nested interactive elements without invalid-HTML hydration errors
- fix(repo-combobox): toggle all-repos selection on repeat click
* fix(tasks): route Use CTA to item's own repo in cross-repo view
handleUseWorkItem previously referenced a removed 'repoId' state; use item.repoId so launching from a merged cross-repo list targets the correct repo.
* test(e2e): add tasks page smoke test