Add "Go to Hadith Number" input to collection navigation

[mahmoodhamdi]

Summary

Adds a "Go to Hadith Number" input to the collection navigation flow so users
can jump directly to a specific hadith instead of scrolling through a book or
using the browser's in-page find.

A new view widget (collection/_go_to_hadith.php) renders a numeric input and
a "Go" button. JavaScript validates the input and builds the
/<collectionName>:<hadithNumber> URL, which the existing
actionHadithByNumber route already handles (including the 301 redirect that
strips leading zeros).

The widget is included in:

• collection/index.php — the collection landing page (e.g. /bukhari)
• collection/dispbook.php — the book page and single-hadith page
  (e.g. /bukhari/1, /bukhari:1)

Implementation notes

• Numeric-only input is enforced via type="number", pattern="[0-9]*",
  inputmode="numeric", and a client-side regex. No server-side validation
  is needed since the existing route already handles bad inputs.
• $collectionName is passed into JavaScript via json_encode to prevent
  XSS.
• The form/input IDs are suffixed with uniqid() so the widget can appear
  more than once on the same page without ID collisions.
• Styling references the same CSS variables already defined by the search
  box widget (--chip-selected-bg, --border-color, --primary-text-color,
  --secondary-text-color), so the field picks up the existing light/dark
  themes.
• WebKit/Firefox spinner buttons on the number input are hidden to keep the
  layout tidy.

No new server-side endpoints, no new dependencies, no DB changes.

Fixes #153

Test plan

• Valid number → navigates to /<collection>:<number>
• Enter key submits the same as the "Go" button
• Empty input → focuses the input, no navigation
• Non-numeric input → blocked by input attributes; regex fallback
  prevents navigation if bypassed
• Leading zeros (01 → 1) stripped client-side; the existing
  server-side 301 redirect remains as a fallback
• php -l clean on all changed files

[ahadith]

@fsid could you please review?