v1.9.1: fix world map rendering and resolve eight small TODO items

World map:
- Fix zero-padded ISO numeric ids leaving 31 countries unrendered
  (Brazil, Australia, Belgium, Austria, Algeria and more)
- Fix Russia and Fiji smearing across the full map width at the antimeridian
  by unwrapping ring longitudes and drawing them at both edges
- Crop to 84N-60S, add evenodd fill rule, 174 countries rendered

Improvements:
- Logger::tail() reads backwards in chunks instead of loading the whole file
- External links get rel=noopener noreferrer in footer and Markdown content
- formatDisplayName() cleaned up and guarded against empty input
- Export statistics as CSV (Excel BOM) or JSON
- GeoIP database auto-updates when older than 35 days
- Editor shortcuts Ctrl/Cmd+S to save and Ctrl/Cmd+N for a new page
- Live search filter in the admin content browser
- Content versioning with timestamped .bak copies in content/-backups/

Also removes eight stale TODO entries that were already implemented

cms/core/class/Logger.php

@@ -123,20 +123,71 @@ class Logger {
     
     /**
      * Get last N lines from log file
-     * 
+     *
+     * Reads the file backwards in chunks so large log files never have to be
+     * loaded into memory in their entirety.
+     *
      * @param int $lines Number of lines to retrieve
-     * @return array Log lines
+     * @return array Log lines (including trailing newlines, oldest first)
      */
     public static function tail($lines = 100) {
         if (!self::$logFile || !file_exists(self::$logFile)) {
             return [];
         }
-        
-        $file = @file(self::$logFile);
-        if ($file === false) {
+
+        $lines = max(1, (int)$lines);
+
+        $handle = @fopen(self::$logFile, 'rb');
+        if ($handle === false) {
             return [];
         }
-        
-        return array_slice($file, -$lines);
+
+        if (fseek($handle, 0, SEEK_END) !== 0) {
+            fclose($handle);
+            return [];
+        }
+
+        $fileSize = ftell($handle);
+        if ($fileSize === false || $fileSize === 0) {
+            fclose($handle);
+            return [];
+        }
+
+        $chunkSize = 8192;
+        $position = $fileSize;
+        $buffer = '';
+        $newlineCount = 0;
+
+        // Read backwards until we have enough newlines or reach the start
+        while ($position > 0 && $newlineCount <= $lines) {
+            $readSize = (int)min($chunkSize, $position);
+            $position -= $readSize;
+
+            if (fseek($handle, $position, SEEK_SET) !== 0) {
+                break;
+            }
+
+            $chunk = fread($handle, $readSize);
+            if ($chunk === false) {
+                break;
+            }
+
+            $buffer = $chunk . $buffer;
+            $newlineCount = substr_count($buffer, "\n");
+        }
+
+        fclose($handle);
+
+        if ($buffer === '') {
+            return [];
+        }
+
+        // Split while keeping the newline characters, matching file() behaviour
+        $result = preg_split('/(?<=\n)/', $buffer, -1, PREG_SPLIT_NO_EMPTY);
+        if ($result === false) {
+            return [];
+        }
+
+        return array_slice($result, -$lines);
     }
 }