* docs: add CLAUDE.md for Claude Code guidance
* fix: handle missing settings table in installation middlewares
RedirectIfInstalled crashed with "no such table: settings" when the
database_created marker file existed but the database was empty.
Changed to use isDbCreated() which verifies actual tables, and added
try-catch around Setting queries in both middlewares.
* feat: pre-select database driver from env in installation wizard
The database step now reads DB_CONNECTION from the environment and
pre-selects the matching driver on load, including correct defaults
for hostname and port.
* feat: pre-select mail driver and config from env in installation wizard
The email step now fetches the current mail configuration on load
instead of hardcoding the driver to 'mail'. SMTP fields fall back
to Laravel config values from the environment.
* refactor: remove file-based DB marker in favor of direct DB checks
The database_created marker file was a second source of truth that
could drift out of sync with the actual database. InstallUtils now
checks the database directly via Schema::hasTable which is cached
per-request and handles all error cases gracefully.
