fix: Complete memory leak fix with shortcode context tracking

The v0.4.1 fix was incomplete - shortcodes called get_*_data() methods
directly, bypassing the recursion tracking in get_post_data().

Changes:
- Added $in_shortcode_context flag to TemplateLoader
- Added enter/exit_shortcode_context() methods
- All shortcode render methods now enter context before data loading
- When in shortcode context, the_content filter is always skipped

This fully prevents infinite recursion when post content contains
FediStream shortcodes that would otherwise recursively render.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

includes/Frontend/TemplateLoader.php

@@ -35,6 +35,43 @@ class TemplateLoader {
      */
     private const MAX_RECURSION_DEPTH = 3;
 
+    /**
+     * Whether we're currently in a shortcode rendering context.
+     * When true, the_content filter is skipped to prevent recursive shortcode processing.
+     *
+     * @var bool
+     */
+    private static bool $in_shortcode_context = false;
+
+    /**
+     * Enter shortcode rendering context.
+     * Call this before rendering shortcode content to prevent recursive shortcode processing.
+     *
+     * @return void
+     */
+    public static function enter_shortcode_context(): void {
+        self::$in_shortcode_context = true;
+    }
+
+    /**
+     * Exit shortcode rendering context.
+     * Call this after shortcode rendering is complete.
+     *
+     * @return void
+     */
+    public static function exit_shortcode_context(): void {
+        self::$in_shortcode_context = false;
+    }
+
+    /**
+     * Check if we're in a shortcode rendering context.
+     *
+     * @return bool
+     */
+    public static function is_in_shortcode_context(): bool {
+        return self::$in_shortcode_context;
+    }
+
     /**
      * Constructor.
      */
@@ -213,13 +250,15 @@ class TemplateLoader {
         // Track recursion to prevent infinite loops from shortcodes in content.
         ++self::$recursion_depth;
 
-        // At depth > 1, skip the_content filter to prevent shortcode recursion.
-        $is_nested = self::$recursion_depth > 1;
+        // Skip the_content filter if:
+        // 1. We're in a shortcode context (prevents recursive shortcode processing)
+        // 2. We're at depth > 1 (nested data loading)
+        $skip_content_filter = self::$in_shortcode_context || self::$recursion_depth > 1;
 
         $data = array(
             'id'        => $post->ID,
             'title'     => get_the_title( $post ),
-            'content'   => $is_nested ? wp_kses_post( $post->post_content ) : apply_filters( 'the_content', $post->post_content ),
+            'content'   => $skip_content_filter ? wp_kses_post( $post->post_content ) : apply_filters( 'the_content', $post->post_content ),
             'excerpt'   => get_the_excerpt( $post ),
             'permalink' => get_permalink( $post ),
             'thumbnail' => get_the_post_thumbnail_url( $post->ID, 'large' ),