docs: update CLAUDE.md with branching workflow, E2E testing commands

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

CLAUDE.md

@@ -19,8 +19,10 @@ bun run db:generate         # Generate Drizzle migration from schema changes
 bun run db:push             # Apply migrations to gearbox.db
 
 # Testing
-bun test                    # Run all tests
+bun test                    # Run all unit/integration tests
 bun test tests/services/item.service.test.ts  # Run single test file
+bun run test:e2e            # Run Playwright E2E tests
+bun run test:e2e:ui         # Playwright UI mode for debugging
 
 # Lint & Format
 bun run lint                # Biome check (tabs, double quotes, organized imports)
@@ -55,9 +57,16 @@ bun run build               # Vite build → dist/client/
 - **Timestamps**: stored as integers (unix epoch) with `{ mode: "timestamp" }`.
 - Tables: `categories`, `items`, `threads`, `threadCandidates`, `setups`, `setupItems`, `settings`, `users`, `sessions`, `apiKeys`.
 
-### Testing (`tests/`)
-- Bun test runner. Tests at service level and route level.
-- `tests/helpers/db.ts`: `createTestDb()` creates in-memory SQLite with full schema and seeds an "Uncategorized" category. When adding schema columns, update both `src/db/schema.ts` and the test helper's CREATE TABLE statements.
+### Testing (`tests/` and `e2e/`)
+- **Unit/integration**: Bun test runner (`bun test`). Tests at service level and route level.
+- `tests/helpers/db.ts`: `createTestDb()` creates in-memory SQLite via Drizzle migrations and seeds an "Uncategorized" category.
+- **E2E**: Playwright (`bun run test:e2e`). Tests in `e2e/` run against a seeded SQLite database with the server in production mode. Seed script: `e2e/seed.ts`.
+
+## Branching
+
+- **Develop** is the main branch. Keep it clean — don't commit large feature work directly.
+- For each new brainstorming/implementation session, create a feature branch off Develop (e.g., `feature/setup-impact-preview`, `fix/error-handling`).
+- Merge back to Develop via PR or fast-forward merge when the work is complete and verified.
 
 ## Path Alias