Re-applies the deltas that mid-stack blob reverts discarded, and merges
main's round-9 work into the v2-owned surfaces:

- settings: main's Integrations page (#7082) coexists with the branch's
  Scheduled Tasks page in the path union, section labels, icons, and
  search catalog
- contracts: main's preview appearance/zoom/viewport settings imports
  restored beside the branch's modelSelection home for ModelSelection
- mobile: main's built-in themes (#6619) re-applied to the v2 thread
  screens and work log (useThemeColor over hand-rolled color-scheme
  ternaries)
- MessagesTimeline: main's #7157 cleanup adopted (toolCallExpandedBody
  class name unexported, implementation-detail test dropped)
- ChangedFilesTree: main's styled tooltip (#7209) carrying the v2 runId
- pullRequestDetail tests: branch's row-action coverage renamed onto
  main's buildAddSelectionToAgentHandoff (#6597)
- lint: migrated the six branch-owned native title tooltips that main's
  new no-native-title-tooltip rule (#7209) flags to styled Tooltips
  (GitActionsControl, QueuedRunsControl, TimelineSystemDivider,
  MessagesTimeline intent badge and MCP tool logo)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>