v0.6.3: hide the paid city lots from users without a ParkSmarter account

The green lots are the map's only paid category ("City lots - Paid hourly or
permit"); paying for them goes through ParkSmarter, so they are no use to
someone browsing without an account. Every other category is free street
parking with a posted time limit and needs nothing.

Gated by category rather than by an id list. Two lots were named (off Oak St
and off N 3rd Ave) and then the beach ones, which together is every green lot
on the map — and an id list would silently break the next time the map is
regenerated from a new PDF, since ids are positional.

- Paid lots are filtered out of the overlay when signed out, so they are
  neither drawn nor tappable.
- "Park here" still detects them, so standing in one explains that it needs an
  account instead of reporting no parking nearby.
- The area screen guards too, in case one is reached with a stale nav param.
- Server carries an optional per-area requiresAccount override for a lot that
  turns out to take payment another way. Null means "use the category
  default", so an unset value can't be confused with an explicit false.

The new column needs a real migration: CREATE TABLE IF NOT EXISTS does not add
a column to a table that already exists, so an already-deployed server would
have kept the old schema. Covered by a test that builds the pre-migration
table and then opens it.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

app/app.json

@@ -3,14 +3,14 @@
     "name": "BigBrainParking",
     "slug": "bigbrainparking",
     "scheme": "bigbrainparking",
-    "version": "0.6.2",
+    "version": "0.6.3",
     "orientation": "portrait",
     "userInterfaceStyle": "automatic",
     "newArchEnabled": true,
     "icon": "./assets/icon.png",
     "android": {
       "package": "top.mowden.bigbrainparking",
-      "versionCode": 23,
+      "versionCode": 24,
       "edgeToEdgeEnabled": true,
       "adaptiveIcon": {
         "foregroundImage": "./assets/adaptive-icon.png",