Fix helpers/config: timezone, comment leak, silent misconfig, cache perms

- Database.php: pin MySQL session time_zone to the configured named zone
  (mysql.time_zone tables now loaded on the DB) with a fixed-offset
  fallback, so NOW()/TIMESTAMP and PHP agree regardless of the DB server's
  SYSTEM tz. Best-effort, never fatals the connection.
- NotificationHelper: redact comment-body previews for internal/
  confidential tickets in sendCommentNotification and notifyWatchers so
  they are not leaked to the shared Matrix notify list (new $visibility
  param; callers wired in the API batch).
- config.php: die with a clear error if parse_ini_file fails instead of
  silently falling back to insecure defaults (empty DB pass / proxies).
- CacheHelper: create cache dir 0700 and cache files 0600 so other local
  users cannot read or poison security-relevant cached data.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

helpers/Database.php

@@ -57,6 +57,32 @@ class Database
         // Set charset to utf8mb4 for proper Unicode support
         $conn->set_charset('utf8mb4');
 
+        // Pin the MySQL session time zone to the app's configured zone so that
+        // NOW()/CURRENT_TIMESTAMP and PHP agree on wall-clock time regardless of
+        // the DB server's SYSTEM tz. Prefer the named zone (requires the
+        // mysql.time_zone_* tables); if that isn't available, fall back to the
+        // fixed numeric offset PHP computes for the same zone. Best-effort: a
+        // failure here must never fatal the connection.
+        $tz = $GLOBALS['config']['TIMEZONE'] ?? 'UTC';
+        try {
+            $escaped = $conn->real_escape_string($tz);
+            try {
+                // mysqli throws (does not return false) on failure under the
+                // default PHP 8.1+ report mode, so catch it rather than testing
+                // the return value.
+                $conn->query("SET time_zone = '{$escaped}'");
+            } catch (\Throwable $inner) {
+                // Named zone unavailable (mysql.time_zone_* not populated) — fall
+                // back to a fixed numeric offset so PHP and MySQL still agree on
+                // wall-clock time regardless of the DB server's SYSTEM tz.
+                $offset = (new DateTime('now', new DateTimeZone($tz)))->format('P');
+                $escapedOffset = $conn->real_escape_string($offset);
+                $conn->query("SET time_zone = '{$escapedOffset}'");
+            }
+        } catch (\Throwable $e) {
+            error_log('Database: failed to set session time_zone: ' . $e->getMessage());
+        }
+
         return $conn;
     }