Quiet non-actionable startup warnings

[dxqb]

Summary

Suppress a handful of specific, noisy-but-harmless messages emitted while launching the UI and starting training:

• diffusers/transformers logger.warning() lines (Modular Diffusers experimental notice, unexpected-config-attributes, unrecognized loss_type) via filters on the exact emitting loggers
• huggingface_hub local_dir_use_symlinks deprecation and the torch.compile inductor performance notes via warnings/logger filters
• Qt gnome portal dbus errors via QT_LOGGING_RULES
• tensorboard subprocess banner/notices by discarding its stdout/stderr

Each filter targets one specific message, so other warnings from the same libraries still come through.

Test plan

• pre-commit run --all-files passes
• Launched the affected UI or script and exercised the change
• Tested with at least one real preset / config when relevant (note which: ____)

AI assistance

• AI-assisted — I have read every line in this diff and can defend each change