fix: resolve PHPCS errors — remove short ternaries and fix docblock placement

- Replace 4 short ternary operators (?:) with explicit conditionals in Cost_Tracker
- Move declare(strict_types=1) after file-level docblocks in 3 template files
  (PHPCS requires docblock immediately after opening PHP tag)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

peptide-news-plugin.php

@@ -1,5 +1,4 @@
 <?php
-declare( strict_types=1 );
 /**
  * Plugin Name:       Peptide News Aggregator
  * Plugin URI:        https://github.com/peptiderepo/peptide-news-plugin
@@ -15,6 +14,8 @@ declare( strict_types=1 );
  * Requires PHP:      7.4
  */
 
+declare( strict_types=1 );
+
 // Abort if called directly.
 if ( ! defined( 'WPINC' ) ) {
 	die;