Clean up build artifacts and enhance .gitignore

- Removed ~25k build artifact files (node_modules, .next, dist, out)
- Enhanced .gitignore with comprehensive Node.js, Next.js, and build patterns
- Removed generated web assets from pkg/web (HTML, CSS, JS build outputs)
- Added environment files, cache directories, and runtime files to .gitignore
- Repository size reduction: ~688MB of unnecessary build artifacts removed

This significantly reduces repository size and ensures clean version control
by only tracking source files rather than generated build outputs.

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

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

.gitignore

@@ -54,7 +54,46 @@ old-docs/
 test/bzzz-*
 test/*.sh
 
+# Node.js and npm
+node_modules/
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+.npm
+.yarn-integrity
+package-lock.json.bak
+
 # Next.js build artifacts
 .next/
 out/
-node_modules/
+.vercel/
+.turbo/
+
+# Build and cache directories
+dist/
+build/
+*.tsbuildinfo
+.cache/
+
+# Environment files
+.env
+.env.local
+.env.development.local
+.env.test.local
+.env.production.local
+
+# Runtime files
+*.pid
+*.pid.lock
+
+# Coverage and testing
+coverage/
+.nyc_output/
+.jest/
+
+# Generated web assets (embedded files)
+pkg/web/*.html
+pkg/web/*.txt
+pkg/web/assets/
+pkg/web/_next/
+pkg/web/404/