Merges FN-5218: adds hash mention support (`#`) in chat composers, grouping task and file reference results in a unified popup, with wiring into `ChatView` and `QuickChatFAB`, plus test coverage and docs. The hook `useFileMention` is extended and refactored, and the file mention popup UI is updated
Fusion-Task-Id: FN-5218
Implements swipe-back gesture support for mobile navigation across ChatView, MissionManager, and PlanningModeModal, wired through a shared navigation history context and covered by a comprehensive test suite (~548 lines of swipe-back tests). A small fixup ensures swipe-back behaves correctly when la
Fusion-Task-Id: FN-4139
Persist chat drafts to storage in the ChatView component, with accompanying test coverage in a new `ChatView.draft.test.tsx` file.
Fusion-Task-Id: FN-4107
