Add plops editor: focus mode, place/move/resize, semantic zoom (#15)

Pansy's core vision: click into a bed, plop plants in its corners, zoom out and
still see what's planted where. Built on the field editor (#11), PlantPicker
(#13), and plantings API (#14).

Data layer
- lib/plantings.ts: ServerPlanting zod shape, EditorPlanting, effectiveCount, and
  a client mirror of the derived-count formula (computeDerivedCount) for live
  resize display; unit-tested.
- lib/objects.ts: /full now types plantings + plants; useCreatePlanting /
  useUpdatePlanting / useRemovePlanting patch the same FullGarden cache with the
  #11 optimistic + 409-rollback contract. A soft-remove drops the plop from the
  active list.

Editor
- store: selectedPlantingId / livePlanting / armedPlant (mutually-exclusive
  object vs plop selection).
- Focus mode: "Plant here" (object inspector) → focusedObjectId; the canvas
  animates fitToRect to the object and dims the rest; a breadcrumb / Escape /
  empty-tap exits. focusedObjectId mirrors to ?focus (deep-linkable, survives
  reload).
- Placing: "+ Add plant" opens the PlantPicker; the chosen plant stays armed for
  repeat placement; tapping inside the focused object drops a plop (default
  radius max(1.5·spacing, 15cm)) in the object's local frame.
- Manipulating: PlopOverlay (drag to move, edge handle to resize, one PATCH per
  gesture) + PlopInspector (change plant, radius, count override vs live derived,
  label, planted date, soft-remove).
- PlopMarker semantic zoom (px/cm bands): far = flat color patch + a dominant-
  plant tint on the object; mid = circle + emoji; near = + name + count. Plops
  render inside each object's rotated group, so moving/rotating a bed carries
  them with no planting writes.

tsc --noEmit clean; 24/24 vitest; production build green.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01JdQpdYYsTgtkJBxbcpAszi

web/src/editor/Inspector.tsx

@@ -26,10 +26,12 @@ export function Inspector({
   object,
   gardenId,
   unit,
+  onFocus,
 }: {
   object: EditorObject
   gardenId: number
   unit: UnitPref
+  onFocus?: () => void
 }) {
   const update = useUpdateObject(gardenId)
   const del = useDeleteObject(gardenId)
@@ -94,6 +96,12 @@ export function Inspector({
         </button>
       </div>
 
+      {object.plantable && onFocus && (
+        <Button onClick={onFocus} className="w-full">
+          🌱 Plant here
+        </Button>
+      )}
+
       <TextField
         label="Name"
         name="name"