Update wiki for 0.5.0: store configs, N-panel rework, fixes
- Store-Configurations.md: new page (7) documenting the store-config preview — switching configs, configuration sets, the color picker, wheels (tire brand, twin wheels, shader-exact rims, None), rim color
- _Sidebar.md: add "7. Store configurations"
- N-Panel-Tools.md: match the reworked N-panel — Material Switch now uses the "Only selected" checkbox + Debug/Export material buttons; Snow & Ice, Invisible in GE and the LOD toggle merged into a single Visibility panel; Prepare for Export and Tree Season moved to the tab header
- Exporting.md: document the one-click Prepare for Export; fix stale button names in the manual checklist; add the wheels "None" step; armature -> zzz_armature
- Preferences.md: document the 6th Import Default, "Load XML with the same name automatically" (preference only, on by default)
- Importing.md: fix stale panel reference (Visibility panel); note the automatic config-XML load after import
- i3dMappings.md: drop the stale "bones are not assigned" limitation (joints now round-trip and get their mappings); real remaining case is mappings pointing into a non-imported referenced sub-i3d
Added descriptions for i3dMapping feature
N-Panel page updated and images / gifs added
docs: add usage wiki (install, preferences, import, N-panel, export)