refactor(nav): share the context aware create action between the bottom navs

The centre button resolved its target in two copies of the same hook. useCreateAction now holds it once, with the phone only branches (gallery upload, atlas search, collections) behind a flag.

client/src/mobile/components/MBottomNav.tsx

@@ -1,75 +1,16 @@
 import { useEffect, useState } from 'react'
-import { useNavigate, useLocation, useMatch } from 'react-router'
+import { useNavigate, useLocation } from 'react-router'
 import { useSettingsStore } from '../../store/settingsStore'
 import { useTranslation } from '../../i18n'
-import { useJourneyStore } from '../../store/journeyStore'
 import { ChevronRight, MoreHorizontal, Plus, Search, Upload } from 'lucide-react'
 import type { LucideIcon } from 'lucide-react'
 import { normalizeAppearance } from '@trek/shared'
 import { useNavItems, splitMobileNav } from '../../components/Layout/navItems'
+import { isNavItemActive, useCreateAction } from '../../components/Layout/useCreateAction'
 import MFab from './MFab'
 
 interface NavItem { to: string; label: string; icon: LucideIcon }
 
-// The centre "+" means something different per context: inside a trip it adds a
-// place, on the journey list it starts a journey (deliberate deviation from the
-// demo, which reserves the FAB for entries — the list has no journey to add
-// into yet), inside a journey it adds an entry, on the atlas it opens the
-// country search, on collections it adds a place to the active list —
-// everywhere else it creates a new trip. Pages pick the intent up from the
-// query params. The result is unused on /vacay: that screen draws its own centre
-// FAB, so the dock yields the slot instead (see screenFabSlot below, #1811).
-function useCreateAction(): { label: string; run: () => void; upload?: boolean } {
-  const navigate = useNavigate()
-  const { t } = useTranslation()
-  const galleryOpen = useJourneyStore(state => state.mobileGalleryOpen)
-  const inTrip = useMatch('/trips/:id')
-  const inJourney = useMatch('/journey/:id')
-  const onJourneyList = useMatch('/journey')
-  const onAtlas = useMatch('/atlas')
-  const onCollections = useMatch('/collections')
-  const inCollection = useMatch('/collections/:id')
-
-  if (inTrip) {
-    // The "+" is context-aware per active tab: Bookings → reservation,
-    // Transports → transport, Costs → expense. Tabs without a create modal
-    // (lists / files / collab) fall through to adding a place. #1349
-    const id = inTrip.params.id
-    const tripTab = typeof sessionStorage !== 'undefined' ? sessionStorage.getItem(`trip-tab-${id}`) : null
-    if (tripTab === 'finanzplan') return { label: t('costs.addExpense'), run: () => navigate(`/trips/${id}?create=expense`) }
-    if (tripTab === 'buchungen') return { label: t('reservations.addManual'), run: () => navigate(`/trips/${id}?create=reservation`) }
-    if (tripTab === 'transports') return { label: t('transport.addManual'), run: () => navigate(`/trips/${id}?create=transport`) }
-    return { label: t('places.addPlace'), run: () => navigate(`/trips/${id}?create=place`) }
-  }
-  if (inJourney) {
-    // Context-aware per tab, like the trip's "+": the Gallery holds photos, so
-    // there the one big action is uploading one. Read from sessionStorage
-    // because the tab is the screen's own state and the dock is a sibling —
-    // exactly how the trip tabs hand theirs over.
-    const journeyId = inJourney.params.id
-    if (galleryOpen) {
-      return { label: t('common.upload'), run: () => navigate(`/journey/${journeyId}?create=photo`), upload: true }
-    }
-    return { label: t('journey.detail.addEntry'), run: () => navigate(`/journey/${journeyId}?create=entry`) }
-  }
-  if (onJourneyList) {
-    return { label: t('journey.new'), run: () => navigate('/journey?create=1') }
-  }
-  if (onAtlas) {
-    return { label: t('atlas.searchCountry'), run: () => navigate('/atlas?search=1') }
-  }
-  if (onCollections || inCollection) {
-    // Picking a list moves the route to /collections/:id, so the exact match
-    // alone dropped the "+" through to creating a trip — the one state the
-    // screen is normally used in (#1930). The handoff keeps the id, otherwise
-    // adding would land on "All saved" and the sheet would ask for the list the
-    // user is already looking at.
-    const path = inCollection ? `/collections/${inCollection.params.id}` : '/collections'
-    return { label: t('collections.addPlace'), run: () => navigate(`${path}?create=place`) }
-  }
-  return { label: t('dashboard.newTrip'), run: () => navigate('/dashboard?create=1') }
-}
-
 /**
  * Floating glass dock of the mobile shell. Same tab/gating/"+" logic as the
  * legacy BottomNav (addons, ?create= contract), redesigned as the demo's icon
@@ -81,7 +22,9 @@ export default function MBottomNav() {
   const { t } = useTranslation()
   const navigate = useNavigate()
   const location = useLocation()
-  const create = useCreateAction()
+  // The "+" result is unused on /vacay: that screen draws its own centre FAB, so
+  // the dock yields the slot instead (see screenFabSlot below, #1811).
+  const create = useCreateAction(true)
   const [moreOpen, setMoreOpen] = useState(false)
 
   // Close the popover when the route changes underneath it (browser back etc.).
@@ -97,8 +40,7 @@ export default function MBottomNav() {
   const dockItems: NavItem[] = split.bar
   const moreItems: NavItem[] = split.more
 
-  const isActive = (to: string) =>
-    to === '/dashboard' ? location.pathname === '/dashboard' : location.pathname.startsWith(to)
+  const isActive = (to: string) => isNavItemActive(location.pathname, to)
   const moreActive = moreItems.some(item => isActive(item.to))
 
   // The FAB gives way to a decorative logo slot on screens without an add