7.0.0-RC1

refactor(injector): Widen type hints from Horde_Injector to Horde_Injector|Injector
refactor: Migrate from strftime to IntlDateFormatter
fix: Simplify Torben's previous PR on download URLs
test: Cover KeyStorage class
feat: Add some modern types to KeyStorage and optionally throw on error.
feat: Emit a warning notification if the SMIME key appears corrupt
feat: Emit a warning notification if the key appears corrupt
fix: Wrong prefix for PSR-4
feat: base64-encode keys for storage
Refactor download URL extraction logic
docs: Upgrade note on hashtable driver abuse as a temp fs
refactor: Accept Horde\Util\Variables in most places which accept Horde_Variables
docs: icon license
style: Changed CSS and icon assets to Lucide Icons with proper attribution
fix: Make imp more explicit when email address was not configured
docs(conf.php.dist): Add missing keys
fix: guard convertCharset() against null getContents() for PHP 8.1+
fix: Null safety
docs: Add documented example config file
fix: More defensive code when trying to drop tables
docs: Clarify where to put local overrides