Pagination fixes, blog page chooser, Events & Projects redesign

Pagination
- Fix the broken mobile layout on News & Projects: page numbers on top,
  Previous / Next side-by-side below (shared .pagination component)
- Add a page chooser to the Blog: rewrite blog-filter.js to combine the
  topic filter with client-side pagination (page size 6), add the pager
  markup (all 3 languages) and .blog-pagination styles; it auto-hides
  when a topic has one page

Events & Projects — match the Blog/News design
- Hero: uppercase letter-spaced eyebrow, sentence-case bold title, lead
  subtitle, soft gradient; drop the redundant hero subscribe form and the
  placeholder copy (signup still available in the bottom newsletter CTA);
  align MK/SI titles to "Events & projects"
- Filters: News-style pills (dark active), left-aligned, with the thin
  separator line below; .filter-inner wrapper aligns pills/separator with
  the grid
- Spacing: reduce the gap under the header, add space below the filter so
  the separator / Events sub-filter no longer collide with "All our
  projects" (these hero/spacing tweaks also tidy the shared About/Get-to-know/
  Timeline heroes)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

mk/blog/index.html

@@ -263,6 +263,11 @@
                         </div>
                     </article>
                 </div>
+                <nav class="pagination blog-pagination" data-page-size="6" hidden>
+                    <button type="button" class="pagination-arrow" data-nav="prev"><i class="fas fa-arrow-left" aria-hidden="true"></i> Претходна</button>
+                    <div class="pagination-numbers"></div>
+                    <button type="button" class="pagination-arrow" data-nav="next">Следна <i class="fas fa-arrow-right" aria-hidden="true"></i></button>
+                </nav>
         </section>
     </main>