Plants mode: recent-planted quick strip + clump/rows fill (#100)

Two things Steve asked for, both in the #99 Plants mode:

- A "Recent" strip of the plants most recently planted IN THIS GARDEN
  (recentlyPlantedIds — derived from actual plantings, newest first, unique;
  NOT the manual localStorage tray), as tap-to-arm chips. So re-planting
  "more of the same" is one tap, no picker. Hidden until something's planted.
- A clump/rows fill control (FillControl), shown once a plant is armed:
  pick a layout, "Fill bed", and it runs POST /objects/:id/fill region=all
  with the chosen layout — the #77 grid/clump fill the UI could NOT reach
  before (it was agent/REST only). Defaults to rows (a real planting).
  useFillObject mirrors useClearObject: one request, invalidate /full.

Both live in the shared PlantPlacementTools, so desktop's focus toolbar and
the mobile Plants strip get them identically. Fill is capped/validated
server-side (#95) and covered spots are skipped, so re-filling is safe.

Verified live at 390px: the Recent strip shows this garden's tomato/lettuce/
garlic; arming a chip reveals Clump|Rows + Fill bed; fill fires cleanly.
tsc + vitest (95, incl. recentlyPlantedIds) + build green. DESIGN updated.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01H3zbym8Doka2d7D48maSgZ

web/src/lib/plantings.test.ts

@@ -1,5 +1,47 @@
 import { describe, expect, it } from 'vitest'
-import { computeDerivedCount, effectiveCount } from './plantings'
+import { computeDerivedCount, effectiveCount, recentlyPlantedIds, type EditorPlanting } from './plantings'
+
+function plop(over: Partial<EditorPlanting>): EditorPlanting {
+  return {
+    id: 0,
+    objectId: 1,
+    plantId: 1,
+    xCm: 0,
+    yCm: 0,
+    radiusCm: 5,
+    count: null,
+    derivedCount: 1,
+    label: null,
+    plantedAt: null,
+    version: 1,
+    ...over,
+  }
+}
+
+describe('recentlyPlantedIds', () => {
+  it('returns unique plant ids, newest planted first', () => {
+    const got = recentlyPlantedIds([
+      plop({ id: 1, plantId: 10, plantedAt: '2026-05-01' }),
+      plop({ id: 2, plantId: 20, plantedAt: '2026-07-01' }),
+      plop({ id: 3, plantId: 10, plantedAt: '2026-06-01' }), // dup plant, later
+    ])
+    // 20 (Jul) before 10 (its most recent plop is Jun); 10 appears once.
+    expect(got).toEqual([20, 10])
+  })
+
+  it('breaks a same-day tie by newer plop id, and sorts undated last', () => {
+    const got = recentlyPlantedIds([
+      plop({ id: 5, plantId: 30, plantedAt: null }),
+      plop({ id: 6, plantId: 40, plantedAt: '2026-07-01' }),
+      plop({ id: 7, plantId: 50, plantedAt: '2026-07-01' }),
+    ])
+    expect(got).toEqual([50, 40, 30]) // id 7 > 6 on the same day; undated 30 last
+  })
+
+  it('is empty for no plantings', () => {
+    expect(recentlyPlantedIds([])).toEqual([])
+  })
+})
 
 describe('computeDerivedCount', () => {
   it('mirrors the server formula max(1, round(π·r²/spacing²))', () => {