fix(AppShell): correct Inventory take/drop editor and Attributes editor gaps

[alexwarren]

Summary

Fixes several gaps in the AppShell editor found while comparing it against the v5 desktop/web editors:

Inventory tab (Take/Drop):

• AddDropdownTypeValues (WASM bridge) never resolved bool values to "boolean", so the Take/Drop dropdown showed blank instead of defaulting to "Default behaviour", and the "Object can be taken"/"Take message" controls never rendered (no boolean branch existed in PropertyEditor.svelte's "multi" control renderer).
• SetMultiType had no "boolean" case, so switching the dropdown back from "Run script" to "Default behaviour" silently failed (hit the unknown-type fallback).
• Forwarded the ASLX <checkbox> caption through a new checkboxCaption field on ControlInfo so the checkbox label ("Object can be taken") renders correctly.

Attributes editor:

• elementtype/type are now fully locked (type dropdown + value), since they identify the element and must never be hand-edited.
• name's type dropdown is locked to string, but its value stays editable (renaming still works).
• Added an "Add Change Script" button (creates a changed<attr> script attribute), matching v5's WFAttributesControl.AddChangeScriptAllowed — including for inherited attributes, which v5 also allows (unlike delete, which v5 blocks for inherited attributes).
• When a changed<attr> already exists, shows a "Go to Change Script" button instead, which selects and scrolls to that attribute.

Test plan

• dotnet build src/WasmEditor/WasmEditor.csproj — 0 errors/warnings
• npm run check (svelte-check) in src/AppShell — 0 errors/warnings
• Verified live in the editor (local draft game, player object):
  • Take dropdown defaults to "Default behaviour"; "Object can be taken"/"Take message" render and toggle correctly
  • Switching Take from "Run script" back to "Default behaviour" correctly clears the script and resets to a boolean checkbox
  • elementtype/type rows: type dropdown and value both disabled
  • name row: type dropdown disabled, value still editable
  • "Add Change Script" on take creates changedtake and selects it; hidden for elementtype/type/name
  • "Go to Change Script" shown for inherited isopen (has changedisopen) and correctly navigates to it
• No console errors during manual verification

🤖 Generated with Claude Code