feat(fuji): UI polish, workspace actions, state architecture, and date fields

[braden-w]

Fuji had the bones of a journal app but no personality. The sidebar was static, search did nothing visible, entries had no timestamps the user could control, and the whole state layer was a single 300-line component. This reworks the app from data layer through UI.

The workspace definition now owns entry lifecycle through typed actions. Creating and updating entries goes through withActions() instead of ad-hoc table.set() calls scattered across components:

const workspace = createFujiWorkspace()
  .withActions(({ tables, kv }) => ({
    entries: {
      create: defineMutation({
        input: Type.Object({ title: Type.String(), type: Type.String() }),
        handler: ({ title, type }) => {
          const id = generateId();
          tables.entries.set({ id, title, type, ... });
          return { id };
        },
      }),
      update: defineMutation({
        input: Type.Object({ id: Type.String(), ... }),
        handler: ({ id, ...fields }) => {
          tables.entries.update(id, { ...fields, updatedAt: DateTimeString.now() });
        },
      }),
    },
  }));

---

State went from one monolith to three focused modules.

The old +page.svelte mixed view preferences, entry CRUD, search filtering, and sort logic in one file. Now each concern has its own module that imports the workspace directly:

+page.svelte (orchestration only)
  entries.svelte.ts  (CRUD, active entries, search filtering)
  view.svelte.ts     (sort preference, type/tag filters, view mode)
  workspace.ts       (definition, actions, factory)

Components import state directly instead of receiving it through props. EntriesTable, EntryTimeline, and EntriesSidebar all read from the state modules, which eliminated ~15 prop-drilling chains across the page.

---

The UI got a proper shell. An AppHeader with a command palette (Cmd+K), a resizable sidebar that shows search results inline when a query is active, a SyncStatusIndicator popover for sign-in and connection status, and rich empty states for each view mode.

Entries gained a user-controllable date field backed by the NLP date input from @epicenter/ui. System timestamps (createdAt, updatedAt) moved to a metadata bar inside the editor. Sort preferences persist via workspace KV.

---

The UI package picks up a few pieces too. The NLP date input got renamed from NLPDateInput to NaturalLanguageDateInput, its parsing pipeline was trimmed to just the datetime-string conversion it actually needs, and the timezone combobox was extracted to its own packages/ui/src/timezone-combobox/ module. A GitHubButton component replaces the hand-rolled SVG icon that was duplicated across apps.

Also flattened the fuji file structure: workspace/definition.ts + workspace/workspace.ts collapsed into a single workspace.ts, state/entries-state.svelte.ts became entries.svelte.ts, barrel files deleted, auth.ts inlined into client.ts.

30 files changed, +2154/-619. Stacks on #1644, #1645, #1646 (all merged).