build: configure multi-entry Vite build for reader

- Add reader.ts as second entry point alongside main.ts in vite.config.ts
- Set assetsDir to empty string to output chunks to /static/ root
- Remove reader-shell import from main.ts (loaded separately via reader.js)
- Update .gitignore to exclude web/static/assets/*.js chunks
- Update Bruno environment with new test IDs

.gitignore

@@ -20,6 +20,7 @@ package-lock.json
 # Exception: Downloaded documentation dependencies
 web/static/compiled-*.js
 web/static/*.js
+web/static/assets/*.js
 
 # Downloaded documentation dependencies (tracked in git)
 !web/static/htmx.min.js