Resolve editor interactions, parallel routing, and UI usability

[pcetner]

Editing connected thermal networks could delete neighboring components, leave duplicate nodes, or distort parallel routes. This change makes topology edits transactional and rebuilds the editor interface around a docked inspector and actionable findings.

• Preserve attached components during deletion; merge compatible overlapping nodes; support ideal connections, disconnection, and series/parallel insertion with layout expansion. A drop on a parallel group's shared terminal lead inserts one resistance for the whole group without a bypass wire.
• Preserve right-angle parallel routes during dragging, align boxed/zigzag terminals, and make Count/Arrangement edits explicit Apply/Cancel transactions with Undo/Redo.
• Add canonical Kelvin temperature handling, Fahrenheit and interval conversions, unit/prefix formatting, a contextual scientific picker, and matching embedded font coverage.
• Dock Properties alongside permanent Components and Solve views; simplify menus and toolbar icons; move examples into Files; fix library scrolling, Present, dialog controls, and warning navigation.
• Update documentation, regression fixtures, render baselines and gallery assets. Extend CI to run the new browser and topology/group tests.

Validation: full Python/browser suite, Node topology/group tests, mypy, documentation freshness checks, editor/bundled-wheel build, and visual review of desktop/narrow layouts and routed parallel insertion. Original supplied diagram files are unchanged; their copies are regression fixtures. No deployment is included.