feat(web): refresh settings layout and application icons

[DualChimerra]

Settings now uses the same compact cards and controls as the training configuration screen, with shorter English/Russian labels and explanations in tooltips. The models folder Save button stays disabled when the displayed default path has not changed.

• Reorganize appearance, remote access, download sources, training/queue, dependency status and model cards; keep local model selection in the shared lists.
• Replace the rotating favicons with consistent PNG, ICO and Apple touch icons as part of the interface refresh.
• Update the custom-model guide and the renamed navigation target in the model-selection test; add coverage for editing/resetting the effective models path.

Validation: npm run build (lint, TypeScript and production build) passed; final lint and git diff --check passed. Final frontend suite: 453 passed, 18 failed (471 total). A separate snapshot of main at c951498a produced 452 passed, the same 18 failed (470 total); no additional failing tests remain. Existing failures cover BaseModelSelect, SchemaForm, VersionStatusBadge, QueueDetail, Generate, outdated Settings scenarios, PreviewCompare and PreviewXYGrid. Backend tests were not run because backend code is unchanged. The build retains its large-chunk warning.

Preview rendered in headless Chrome using test fixtures (not live account/model data):

Downloaded model files, the Windows shortcut, one-off path migration script, scratch output and unrelated image assets were left local. Targets the repository's current default branch main; the old dev/master branches referenced in CONTRIBUTING no longer exist.