fix: report modal dialog blocks on connect timeout

[spi3]

Summary

Fixes for issue #12 to improve headless connect timeout diagnostics when TeamSpeak is blocked by modal dialogs.

• Adds optional --timeout-ms to ts connect and passes it to the connect completion wait timeout.
• Adds xwininfo fallback for client inspect-windows when xdotool is unavailable.
• Includes blocked-dialog hints (for each visible title) when connect times out with inspectable windows.
• Updates CLI and tests for timeout parsing and xwininfo fallback coverage.

Testing

• cmake --build /tmp/teamspeak_cli_issue12_build-mock-make --target ts_cli_router_test
• /tmp/teamspeak_cli_issue12_build-mock-make/ts_cli_router_test

Fixes #12