chore: cleanup gitignore and remove stale tracked files

- Remove user-specific files from tracking:
  - .claude/settings.local.json (contains machine-specific paths)
  - backup.json (application state data)
  - logs/server.log (runtime log)
  - test-results/.last-run.json (playwright state)
  - apps/.DS_Store (macOS metadata)
  - apps/app/playwright.config.ts.bak (backup file)

- Add comprehensive gitignore patterns:
  - OS files: .DS_Store, Thumbs.db, Desktop.ini
  - IDE/Editor configs: .vscode/, .idea/, sublime
  - Backup/temp files: *.bak, *.swp, *.tmp, *~
  - Local settings: *.local.json
  - Test artifacts: test-results/, coverage/, .nyc_output/
  - Environment files: .env, .env.local (keeps .example)
  - Build outputs: .turbo/, build/, out/

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/app/playwright.config.ts.bak

@@ -1,30 +0,0 @@
-import { defineConfig, devices } from "@playwright/test";
-
-const port = process.env.TEST_PORT || 3007;
-
-export default defineConfig({
-  testDir: "./tests",
-  fullyParallel: true,
-  forbidOnly: !!process.env.CI,
-  retries: process.env.CI ? 2 : 0,
-  workers: process.env.CI ? 1 : undefined,
-  reporter: "html",
-  timeout: 10000,
-  use: {
-    baseURL: `http://localhost:${port}`,
-    trace: "on-first-retry",
-    screenshot: "only-on-failure",
-  },
-  projects: [
-    {
-      name: "chromium",
-      use: { ...devices["Desktop Chrome"] },
-    },
-  ],
-  webServer: {
-    command: `npx next dev -p ${port}`,
-    url: `http://localhost:${port}`,
-    reuseExistingServer: true,
-    timeout: 60000,
-  },
-});