fix(maps): reduce Google Places API quota usage with persistent caching

P0 — stop the bleeding:
- Honor place.image_url in MapView and TripPlannerPage to skip redundant fetchPhoto calls
- Trim Place Details field mask (drop reviews/editorialSummary from default; new getPlaceDetailsExpanded for inspector)
- Admin toggle places_photos_enabled (default ON) to kill Google photo fetches under quota pressure; Wikimedia unaffected
- Return { photoUrl: null } instead of 204 so client handles disabled state cleanly

P1 — structural fix:
- New placePhotoCache service: persistent disk cache at uploads/photos/google/<sha1>.jpg, atomic writes, stampede dedup via in-flight Map
- Migrations 105-107: google_place_photo_meta table, place_details_cache table, backfill signed Google URLs to stable proxy URLs
- getPlacePhoto rewrites to fetch image bytes directly, store on disk, return /api/maps/place-photo/:id/bytes proxy URL
- Stable proxy URLs written to places.image_url — survive container restarts, no expiry
- New GET /api/maps/place-photo/:placeId/bytes route serving cached files with long-lived Cache-Control
- Place Details DB row cache with 7-day TTL; ?refresh=1 escape hatch
- photoService fast-path: proxy URLs bypass the mapsApi round-trip and go straight to urlToBase64

Bug fixes:
- MapView now requests base64 thumbs for places with proxy image_url (markers were showing color fallback)
- createPlaceIcon accepts /api/maps/place-photo/ URLs as interim fallback while thumb generates
- setSelectedAssignmentId ReferenceError in mobile day-detail handler (use selectAssignment)
- Remove redundant decodeURIComponent on already-decoded Express route param
- Use SHA1 hash for disk filenames to prevent coords:lat:lng pseudo-ID collisions
- Add checkSsrf guard to Wikimedia byte fetch
- Tighten migration 107 LIKE filter to avoid rewriting manually-pasted Google image URLs
- Validate enabled is boolean on PUT /admin/places-photos
- Drop aggressive iconCache.clear() on every thumb arrival

Observability:
- googleFetch() wrapper counts and debug-logs every outbound Google API call with running total

client/src/components/shared/PlaceAvatar.tsx

@@ -1,6 +1,7 @@
 import React, { useState, useEffect, useRef } from 'react'
 import { getCategoryIcon } from './categoryIcons'
 import { getCached, isLoading, fetchPhoto, onThumbReady } from '../../services/photoService'
+import { useAuthStore } from '../../store/authStore'
 import type { Place } from '../../types'
 
 interface Category {
@@ -18,10 +19,12 @@ export default React.memo(function PlaceAvatar({ place, size = 32, category }: P
   const [photoSrc, setPhotoSrc] = useState<string | null>(place.image_url || null)
   const [visible, setVisible] = useState(false)
   const ref = useRef<HTMLDivElement>(null)
+  const placesPhotosEnabled = useAuthStore(s => s.placesPhotosEnabled)
 
   // Observe visibility — fetch photo only when avatar enters viewport
   useEffect(() => {
     if (place.image_url) { setVisible(true); return }
+    if (!placesPhotosEnabled) return
     const el = ref.current
     if (!el) return
     // Check if already cached — show immediately without waiting for intersection
@@ -37,6 +40,7 @@ export default React.memo(function PlaceAvatar({ place, size = 32, category }: P
   useEffect(() => {
     if (!visible) return
     if (place.image_url) { setPhotoSrc(place.image_url); return }
+    if (!placesPhotosEnabled) return
     const photoId = place.google_place_id || place.osm_id
     if (!photoId && !(place.lat && place.lng)) { setPhotoSrc(null); return }