Graceful cache fallback when cache driver is unreachable

[pushpak1300]

When the configured cache driver is unreachable (e.g. database driver with PostgreSQL down, Redis connection refused), Boost throws unhandled exceptions like QueryException. This crashes boost:install, DatabaseSchema, and LastError MCP tools — none of which actually require cache to function.

Solution

Wrapped all cache operations in Laravel's rescue() helper with report: false. Each call site has a natural fallback:

• BoostServiceProvider — cache miss triggers fresh Roster::scan(), failed write is skipped
• DatabaseSchema — falls back to direct getDatabaseStructure() call
• LastError — falls back to reading the log file on disk

Added tests to verify LastError and DatabaseSchema degrade gracefully when cache fails.