Journal UI: write and read season notes where you're already looking (#53)

#52 stores entries; this makes writing one cheap enough that it actually
happens. Notes get written standing in the garden holding a phone, usually
one-handed — if it takes more than a couple of taps from looking at a bed to
typing a sentence, the log stays empty.

So the journal is a tab in the rail #49 settled, and selecting a bed puts a
"📝 Add note" button in the inspector that scopes the journal to that bed and
switches to it. The composer is already open in there rather than behind an
"add" button, which makes it two taps from a selected bed to typing.

The observed date defaults to today in the VIEWER's timezone, not UTC — "today"
means the day you are standing in the garden — and stays editable, because you
write up Saturday's observations on Sunday.

Discoverability is the other half. A log you have to remember exists is a log
nobody reads, so the inspector button carries the note count for that bed and
the Journal tab carries the garden's total: a garden with a season's notes in it
no longer looks identical to an empty one. Those counts come from their own
endpoint, deliberately — the indicator has to work while the journal panel is
closed, which is exactly when the entry list hasn't loaded.

Permissions match the service: anyone who can edit the garden can write, the
author can edit their own text, and the author or the garden owner can delete.
A viewer sees the entries and the count but no composer.

The empty state says what the journal is for rather than just "no entries",
since it starts empty for a whole season's worth of gardens and the reason to
start is the thing worth saying.

Closes #53

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

DESIGN.md

@@ -109,7 +109,7 @@ React 19 + TypeScript + Vite + Tailwind 4 (`@tailwindcss/vite`), `@tanstack/reac
 - **Routes:** `/login`, `/register`, `/gardens` (list), `/gardens/:id` (editor, `?focus=objectId`), `/plants` (catalog). Auth guard on the router root via `/auth/me`.
 - **State:** TanStack Query for all server state (editor keyed on `gardens/:id/full`; optimistic mutations with version-conflict rollback). One small Zustand store for ephemeral editor state only: viewport, selection, focused object, active tool, in-flight drag.
 - **Editor components (`web/src/editor/`):** `GardenCanvas` (svg root + viewport g), `useViewport` (use-gesture pan/zoom/pinch), `ObjectShape`, `PlopMarker` (semantic-zoom branching), `Palette` (drag-to-place object kinds), `EditorRail` (the one side panel), `Inspector`, `HistoryPanel`, `PlantPicker`.
-- **One rail, tabs inside it.** The inspector, history, and later the journal and chat panel all want the same strip of screen; rather than each bolting on its own chrome they are tabs in `EditorRail` — so the canvas is one width instead of a different width per panel, and adding a panel is adding a tab. Selecting an object switches to the Inspector tab automatically, so the rail is never something you operate before you can edit; on a phone the same tabs render in the bottom sheet the inspector already used. Pure geometry helpers (local↔world transforms, unit formatting) in `web/src/lib/geometry.ts`, unit-tested.
+- **One rail, tabs inside it.** The inspector, history, journal, and later the chat panel all want the same strip of screen; rather than each bolting on its own chrome they are tabs in `EditorRail` — so the canvas is one width instead of a different width per panel, and adding a panel is adding a tab. Selecting an object switches to the Inspector tab automatically, so the rail is never something you operate before you can edit; on a phone the same tabs render in the bottom sheet the inspector already used. Pure geometry helpers (local↔world transforms, unit formatting) in `web/src/lib/geometry.ts`, unit-tested.
 
 ## Roadmap