Improve graph/map UX and move contact editing to dedicated pages.

Add viewport controls, collapsible panels with persisted state, filters modal, and refined context menus; preserve map layout on navigation and let contacts be edited with relations on /contacts/:id instead of list modals.

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/src/lib/map/mapLayoutCache.js

@@ -0,0 +1,53 @@
+const STORAGE_KEY = 'sg-map-layout-v1'
+
+const EMPTY = { positions: {}, scale: 1, view: null }
+
+let memoryByMapId = null
+
+function readAll() {
+  if (memoryByMapId) return memoryByMapId
+  try {
+    const raw = sessionStorage.getItem(STORAGE_KEY)
+    memoryByMapId = raw ? JSON.parse(raw) : {}
+  } catch {
+    memoryByMapId = {}
+  }
+  return memoryByMapId
+}
+
+export function readMapLayoutCache(mapId) {
+  if (!mapId) return { ...EMPTY }
+  const all = readAll()
+  const entry = all[String(mapId)]
+  return entry ? { ...EMPTY, ...entry } : { ...EMPTY }
+}
+
+export function writeMapLayoutCache(mapId, { positions, scale, view }) {
+  if (!mapId) return
+  const key = String(mapId)
+  const all = readAll()
+  const prev = all[key] || { ...EMPTY }
+  all[key] = {
+    positions: positions ?? prev.positions,
+    scale: scale ?? prev.scale,
+    view: view ?? prev.view,
+  }
+  memoryByMapId = all
+  try {
+    sessionStorage.setItem(STORAGE_KEY, JSON.stringify(all))
+  } catch {
+    /* sessionStorage quota */
+  }
+}
+
+export function clearMapLayoutCache(mapId) {
+  if (!mapId) return
+  const all = readAll()
+  delete all[String(mapId)]
+  memoryByMapId = all
+  try {
+    sessionStorage.setItem(STORAGE_KEY, JSON.stringify(all))
+  } catch {
+    /* ignore */
+  }
+}