feat(planning): Planning Kanban board UI + graph toggle

[tomymaritano]

Summary

The UI half of the Planning Kanban feature. Stacked on #444 (the data layer) — this PR's base is feature/planning-kanban-data and will auto-retarget to develop once #444 merges. Review #444 first.

Adds the "Planning" sidebar item and the Kanban board it opens. Columns are the 5 Linear-style stages; dragging a card persists via notes.setBoardStage — DB metadata only, the note's markdown is never rewritten ("markdown is sacred").

What's included

Navigation

• NavigationState gains a planning kind + goToPlanning action + selectIsPlanningContext
• Sidebar Planning quick-filter item (KanbanSquare), active-state aware
• App.tsx renders <PlanningBoard> in the editor pane when navigation.kind === 'planning'

Board (components/planning/)

• PlanningBoard — groups Planning-notebook notes into Backlog/Todo/In Progress/In Review/In Staging; Board ↔ Graph toggle
• PlanningColumn — droppable column (native HTML5 DnD, custom application/x-dripnex-note MIME — the app's DnD convention, no new dep)
• PlanningCard — draggable card: title, excerpt, tags, task progress via countMarkdownTasks; click opens the note
• Graph mode reuses GraphView via a new optional filterNotebookId prop that restricts nodes/edges to the Planning notebook

Hooks: useNoteMutations.setBoardStage; BoardStage re-exported from preload.

Testing

• pnpm typecheck (all desktop projects) — green
• pnpm test — green; pnpm lint — green
• pnpm --filter @dripnex/desktop build — bundles successfully
• Manual smoke test pending on pnpm dev (Planning item → board → drag persists → markdown unchanged → graph toggle)

How it connects to the graph

No new graph infra — the existing GraphView / useGraphData / window.dripnex.links are reused; filterNotebookId scopes them to the board's notes (nodes already carry notebookId).

🤖 Generated with Claude Code

[coderabbitai]

Important

Review skipped

Auto reviews are disabled on base/target branches other than the default branch.

🗂️ Base branches to auto review (2)

• main
• develop

Please check the settings in the CodeRabbit UI or the .coderabbit.yaml file in this repository. To trigger a single review, invoke the @coderabbitai review command.

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: ASSERTIVE

Plan: Pro Plus

Run ID: 8b8ef735-a347-42ca-be17-dd9305c8a17a

You can disable this status message by setting the reviews.review_status to false in the CodeRabbit configuration file.

Use the checkbox below for a quick retry:

• 🔍 Trigger review

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch feature/planning-kanban-ui

---

_{Comment @coderabbitai help to get the list of available commands.}