Address #125 review: memoized ink, one fallback color, reactive copy name

- monogramInk is memoized by color string; the canvas asks for every
  visible plop on every frame of a pan (Gadfly, 2/4 models).
- FALLBACK_PLANT_COLOR lives in lib/plants and is used by the canvas, the
  inspector and the garden thumbnail instead of three raw '#97a97c's.
- CopyDialog keeps its proposed "<base> — <year>" in step with the gardens
  list until the person edits the name, so a list that loads after the
  dialog opens can't leave a taken year in the field.
- GardenCard: reflowed the summary comment; no dead fallback on a plan
  name that's already known to parse.
- today() has one import path (lib/dates); the journal re-export is gone.
- CLAUDE.md says what the inspector actually does (a text-compare guard)
  rather than claiming it uses LengthField.

Co-Authored-By: Claude Fable 5 <[email protected]>

web/src/editor/Canvas.tsx

@@ -12,7 +12,7 @@ import {
 import { clampScale, type Point } from '@/lib/geometry'
 import { monogramInk } from '@/lib/monogram'
 import { useCreateObject, useCreatePlanting, useUpdateObject, useUpdatePlanting } from '@/lib/objects'
-import type { Plant } from '@/lib/plants'
+import { FALLBACK_PLANT_COLOR, type Plant } from '@/lib/plants'
 import type { EditorPlanting } from '@/lib/plantings'
 import { formatSize } from '@/lib/units'
 import { kindDef, objectStyle, rectRadius } from './kinds'
@@ -35,10 +35,6 @@ import {
 import { useEditorStore, type Viewport } from './store'
 import type { EditorGarden, EditorObject } from './types'
 
-// A plop whose plant is missing from the catalog (a shared garden's private
-// plant) still needs a color to be drawn in.
-const FALLBACK_PLANT_COLOR = '#97a97c'
-
 const WHEEL_SENSITIVITY = 0.0016
 const ANIM_MS = 520
 const REFIT_THRESHOLD_PX = 60