Wire social-share hook + make Follow button provider-aware

The social-share buttons function was hooked to
projects_after_download_button, but the template never fired that action —
the buttons never rendered. Added a do_action() call after the View Repo
button.

The Follow button hardcoded a GitHub URL and used the GitHub-specific
github-button class (which only acts on github.com). Replaced with a
plain styled link pointing at the owner's actual URL (works for any
provider). Removed the assets/js/buttons.js enqueue since nothing uses
the github-button class anymore.

Renamed the project-github-button CSS class on the View Repo link to
project-repo-button since it's provider-neutral now.

projects-portfolio.php

@@ -115,7 +115,7 @@ function projects_portfolio_handle_download_redirect() {
             // Use wp_redirect() (not wp_safe_redirect()) because the destination
             // is an external host the user has explicitly configured — wp_safe_redirect
             // would reject it and fall back to admin_url().
-            wp_redirect( esc_url_raw( $download_url ), 302 );
+            wp_redirect( esc_url_raw( $download_url ), 302 ); // phpcs:ignore
             exit;
         } else {
             wp_die(
@@ -273,13 +273,9 @@ function projects_portfolio_enqueue_project_styles() {
     }
 
     if ( is_singular( 'projects' ) ) {
-        wp_enqueue_script(
-            'projects-wp-buttons',
-            plugin_dir_url( __FILE__ ) . 'assets/js/buttons.js',
-            array(),
-            PROJECTS_PORTFOLIO_VERSION,
-            true
-        );
+        // assets/js/buttons.js was used to render GitHub-style follow buttons.
+        // The Follow button now uses a plain styled link (works for any provider),
+        // so the script is no longer enqueued.
     }
 }
 add_action( 'wp_enqueue_scripts', 'projects_portfolio_enqueue_project_styles' );