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/JournalTab.tsx

@@ -4,9 +4,9 @@ import { Button, IconButton } from '@/components/ui/Button'
 import { TextAreaField, TextField } from '@/components/ui/Field'
 import { errorMessage } from '@/lib/api'
 import { cn } from '@/lib/cn'
+import { today } from '@/lib/dates'
 import {
   formatObservedAt,
-  today,
   useCreateJournalEntry,
   useDeleteJournalEntry,
   useJournal,