Add "Go to Hadith Number" navigation input field

[anaskex]

This PR adds a new input field in the index view to allow users to jump directly to a specific Hadith number within a collection.

Closes #153

Changes:

• Added field and button in the index search container
• Added JavaScript function to navigate to /collectionName:hadithNumber
• Accepts only numeric input, preventing invalid navigation
• Cross-browser compatible; CSS ensures numeric input looks clean without spinners consistent with design

Benefits:

• Improves usability for users browsing collections
• Safe client-side only navigation, no database or server risk
• Works on all modern browsers and mobile devices

[hasankhan]

Closing as a duplicate of #164, which implements the same Go to Hadith Number feature with a more complete approach: it extracts a reusable collection/_go_to_hadith.php widget, includes it on both the collection landing page and book/single-hadith pages, uses uniqid() to avoid ID collisions when the widget appears multiple times on a page, json_encodes collectionName to prevent XSS, and reuses the existing search-box CSS variables for light/dark theme support. Thanks for the contribution — please feel free to review or build on top of #164.