feat: Implement comprehensive database schema and tRPC routers for clients, projects, tasks, checkpoints, and notes

- Established database schema with five tables using better-sqlite3 and drizzle-orm
- Developed tRPC routers for clients, projects, tasks, checkpoints, and notes with full CRUD operations
- Integrated lazy initialization for electron-store to manage app settings
- Enhanced UI components for task management, including NewTaskDialog and GanttChart
- Implemented search and filter functionalities across various views
- Ensured type safety and strict TypeScript configurations throughout the codebase
- Documented learnings and best practices for future iterations in progress.txt

CLAUDE.md

@@ -0,0 +1,76 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Commands
+
+```bash
+# Development
+source ~/.nvm/nvm.sh && npm start          # Start Electron app with hot-reload
+
+# Build & Package
+source ~/.nvm/nvm.sh && npm run make       # Build distributable packages
+source ~/.nvm/nvm.sh && npm run package    # Package without making installers
+
+# Lint
+source ~/.nvm/nvm.sh && npm run lint       # ESLint over .ts/.tsx files
+
+# Database migrations (Drizzle)
+source ~/.nvm/nvm.sh && npx drizzle-kit generate   # Generate migration from schema changes
+source ~/.nvm/nvm.sh && npx drizzle-kit push        # Push schema directly (dev only)
+```
+
+There is no test suite currently.
+
+## Architecture Overview
+
+Adiuva is a local-first Electron desktop app. The three Electron processes communicate via a custom tRPC↔IPC bridge (the public `electron-trpc` package is incompatible with tRPC v11, so a custom implementation is used).
+
+### Process Boundaries
+
+```
+Renderer (React)  ──ipcLink──►  Preload (contextBridge)  ──IPC──►  Main (tRPC router + SQLite)
+```
+
+1. **Main process** (`src/main/`) — Node.js, owns the database and all business logic
+   - `index.ts` — Window creation, app lifecycle
+   - `ipc.ts` — Custom handler that bridges `ipcMain` to tRPC procedures
+   - `router/index.ts` — All tRPC routers (clients, projects, tasks, checkpoints, notes, settings, ai)
+   - `db/index.ts` — Drizzle + better-sqlite3, WAL mode, singleton `getDb()`
+   - `db/schema.ts` — All table definitions (clients, projects, tasks, checkpoints, notes)
+   - `store.ts` — electron-store for persistent UI settings (e.g., `sidebarCollapsed`)
+
+2. **Preload** (`src/preload/trpc.ts`) — Exposes `window.electronTRPC` with `sendMessage()` / `onMessage()`
+
+3. **Renderer** (`src/renderer/`) — React 19, never accesses Node APIs directly
+   - `lib/ipcLink.ts` — Custom TRPCLink that routes calls through `window.electronTRPC`
+   - `lib/trpc.ts` — `createTRPCReact<AppRouter>()` typed client
+   - `index.tsx` — QueryClient + tRPC + Router providers
+   - All data access is through `trpc.*.*useQuery()` / `trpc.*.*.useMutation()`
+
+### Routing
+
+File-based routing via TanStack Router. Add a file to `src/renderer/routes/` and the route tree (`src/renderer/routeTree.gen.ts`) is auto-regenerated by the Vite plugin on next `npm start`. Routes:
+- `__root.tsx` — Root layout wrapping everything in `AppShell`
+- `index.tsx`, `tasks.tsx`, `timeline.tsx`, `projects.tsx`
+
+### Database
+
+Schema lives in `src/main/db/schema.ts`. Migrations are in `src/main/db/migrations/`. The DB is created in Electron's `userData` directory as `adiuva.db`. On startup, `initDb()` runs non-destructive migrations (CREATE TABLE IF NOT EXISTS).
+
+To add a new table or column: edit `schema.ts`, run `drizzle-kit generate`, then `drizzle-kit push` (dev) or commit the migration file.
+
+### Adding a New Feature (end-to-end pattern)
+
+1. **Schema** — Add table/columns to `src/main/db/schema.ts`
+2. **Router** — Add a tRPC sub-router in `src/main/router/index.ts`, merge it into `appRouter`
+3. **Types** — `AppRouter` is exported from `src/main/router/index.ts` and imported in `src/renderer/lib/trpc.ts` — types flow automatically
+4. **UI** — Create components under `src/renderer/components/<feature>/`, use `trpc.*.*useQuery()` for data
+
+### Key Config Notes
+
+- Vite configs use `.mts` extension (not `.ts`) to avoid ESM/CJS conflicts with electron-forge's externalize-deps plugin
+- `@/*` path alias resolves to `src/renderer/*` (TypeScript + Vite + shadcn/ui all share this alias)
+- shadcn/ui style: **new-york**, base color: **neutral**
+- Icons: **lucide-react** throughout — do not introduce other icon libraries
+- Tailwind 4 (not 3) — use CSS variable theming via `globals.css`, not `tailwind.config.js`