Add account-level crew pool with per-logbook and per-day selection.

Move skipper and crew master data to the user profile pool, replace the logbook crew tab with selection from that pool, inherit crew on new travel days, and sync via new PersonPayload and LogbookCrewSelection models. Includes migration from legacy crew records, tour/demo updates, and i18n.

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

client/src/i18n/locales/en.json

@@ -33,7 +33,7 @@
     "nav": {
       "dashboard": "Dashboard",
       "vessel": "Vessel Profile",
-      "crew": "Crew List",
+      "crew": "Crew",
       "deviation": "Deviation Table",
       "logs": "Logbook Entries",
       "stats": "Statistics",
@@ -607,6 +607,41 @@
       "push_ios_install_hint": "On iPhone/iPad: add the app to your Home Screen (iOS 16.4+) to use push notifications.",
       "push_error": "Could not enable push notifications."
     },
+    "person_pool": {
+      "title": "Core crew & skippers",
+      "subtitle": "Maintain your person pool here — skippers and crew for all logbooks. Select active crew per logbook and travel day from this pool.",
+      "loading": "Loading person pool…",
+      "skippers_section": "Skippers",
+      "crew_section": "Core crew",
+      "add_skipper": "Add skipper",
+      "add_crew": "Add crew member",
+      "edit_skipper": "Edit skipper",
+      "no_skippers": "No skippers in the pool yet.",
+      "no_crew": "No crew members in the pool yet.",
+      "delete_confirm": "Remove this person from the pool?"
+    },
+    "logbook_crew": {
+      "title": "Crew for this logbook",
+      "subtitle": "Choose skipper and crew for this logbook. New travel days inherit this selection by default.",
+      "loading": "Loading crew…",
+      "active_skipper": "Skipper for this logbook",
+      "active_crew": "Crew for this logbook",
+      "no_skippers_in_pool": "No skipper in the pool — add one in your user profile first.",
+      "no_crew_in_pool": "No crew in the pool — add members in your user profile first.",
+      "no_skipper": "No skipper selected",
+      "unnamed": "Unnamed",
+      "save": "Save crew",
+      "saved": "Logbook crew saved.",
+      "selection_only_hint": "You see the crew set by the owner (shared logbook)."
+    },
+    "entry_crew": {
+      "title": "Crew on this travel day",
+      "subtitle": "May differ from the logbook default. Following days inherit from the previous day.",
+      "day_skipper": "Skipper on this day",
+      "day_crew": "Crew on this day",
+      "no_skipper": "No skipper selected",
+      "no_crew": "No crew selected"
+    },
     "crew": {
       "title": "Skipper & Crew Profiles",
       "skipper_section": "Skipper Profile",
@@ -869,9 +904,13 @@
           "title": "Vessel data",
           "body": "Enter your yacht's name, dimensions, and technical details – fill once, use on every travel day."
         },
-        "nav_crew": {
-          "title": "Crew list",
-          "body": "Manage crew members and assign them to travel days later."
+        "profile_crew_pool": {
+          "title": "Core crew & skippers",
+          "body": "In your user profile you maintain a person pool — multiple skippers (e.g. charter) and crew for all logbooks."
+        },
+        "nav_logbook_crew": {
+          "title": "Crew per logbook",
+          "body": "Pick skipper and crew from the pool for this logbook. Travel days inherit this selection by default."
         },
         "nav_stats": {
           "title": "Statistics dashboard",