[UI] Navigation context management — context-return and org switch wipe (Phase 11)

[CRamsan]

Phase 11 — Navigation Context Management

Implement context-return navigation and organization context wipe. This is split from #411 which covered Deep Link Registration, Context-Return Navigation, and Org Context Wipe together.

POL-08: Context-Return Navigation

When a user initiates a child flow from within a specific parent context, successful completion must return them to that parent context.

Cases requiring context-return:

• Unit Detail: Create task from "+" in unit context → return to Unit Detail (Tasks tab) on save
• Unit Detail: View a document → return to Unit Detail (Documents tab) on back
• Request Review List: Approve request, fill AddEditTask → return to Request Review List on save

Implementation: pass returnRoute: Route? as a serialized navigation argument when navigating to the child screen. On successful completion the ViewModel navigates to returnRoute ?: defaultDestination.

POL-09: Organization Context Wipe on Org Switch

When a user switches organizations via the org switcher (from #392):

1. Clear the navigation back stack: navController.navigate(Route.Dashboard) { popUpTo(0) { inclusive = true } }
2. Clear in-memory caches in all Managers — each Manager observes currentOrgId: StateFlow<String?> from OrgContext and calls invalidateCache() on change
3. Update OrgContext singleton with new org ID
4. No stale org-scoped IDs remain in any ViewModel or Manager after the switch

Manager cache invalidation pattern:

init {
    orgContext.currentOrgId
        .distinctUntilChanged()
        .onEach { invalidateCache() }
        .launchIn(managerScope)
}

Dependencies

• [ORG] My Organizations screen + Org Detail + Leave/Transfer ownership (Phase 1) #392 — Org membership/switching (trigger point for POL-09)
• All feature screens (context-return can only be wired once target screens exist)
• [POLISH] Deep link registration for core entities (Phase 11) #411 — Deep Link Registration (separate issue, same epic)

What type of task is this?

Development