feat(Engine): introduce WorldModelVersion 600, restore sync script support

[alexwarren]

Summary

• Restores v5-parity WorldModel version gating: GetInput()/Ask()/ShowMenu() (the plain expression forms) had their >= v540 guard silently dropped during the async/TCS migration, un-deprecating them for every game regardless of declared version. Restored the guard for v540 <= version < v600.
• Introduces a new WorldModelVersion.v600 where these synchronous forms — along with request(Wait)/request(Pause) — are deliberately re-enabled, since they're now backed by TaskCompletionSource-based async blocking rather than real thread blocking and are genuinely more usable than their callback replacements for many authors. New/edited games from the Editor now save as v600.
• Also un-deprecates two more Core.aslx convenience functions in the same spirit: Pause() and WaitForKeyPress() had their bodies swapped for an unconditional error("...is obsolete...") / deleted outright back when the sync-blocking approach was deprecated in favour of callback-based scripts. Since v600 makes the underlying sync-style blocking safe again (TCS-based, not a real thread block), restored both, with their original Script Adder entries, so the Adder shows a proper "Pause for N seconds" / "Wait for key press" control instead of the generic "Raise UI request" panel.
  • Note: this is not a bug fix for already-published games — Core.aslx functions are inlined into a game's .quest file at publish time (see Packager/GameSaver.CanSave), so a game published while Pause()/WaitForKeyPress() were deprecated already carries its own working copy of the old function body and was never broken. The change only affects the authoring experience: games created or edited in the Editor from now on get the restored functions instead of the deprecation stub. See the new "Core Library Semantics" section in CLAUDE.md.
• Restores the "set"/"foreach" expression-template picker that existed in the pre-WASM Quest 5 editor but was never ported to the WASM/AppShell frontend — only "if" templates had a picker UI. Generalized WasmEditorBridge's if-only plumbing (GetIfExpressionTemplates/GetIfExpressionTemplateData) into type-parameterized GetExpressionTemplates(expressionType)/GetExpressionTemplateData(expr, expressionType), and factored ScriptEditor.svelte's duplicated if/else-if template-picker markup into one shared snippet reused by the generic expression-control renderer. This gives GetInput()/ShowMenu() a real "set variable" picker entry ("player's typed input" / "player's choice from a menu").
• Along the way, discovered that (function)Ask/(function)ShowMenu (the Script Adder's callback-sugar forms) aren't redundant with the sync expression forms — they render completely differently (inline numbered hyperlinks via CoreFunctions.aslx, vs. a jQuery UI popup dialog for the expression forms). Kept both addable. Filed Modernize the jQuery UI popup used by Ask()/ShowMenu() expression forms #2006 to track modernizing that popup separately.

Test plan

• dotnet build --configuration Release — clean
• dotnet test --configuration Release — 343/343 passing, including new V600UndeprecationTests covering version gating for GetInput/Ask/ShowMenu/request(Wait)/request(Pause)/Pause()/WaitForKeyPress() across v530/v540/v550/v580/v600
• svelte-check / eslint in src/AppShell — clean
• Manually verified in the running WasmEditor Script Adder: "Wait for key press" and "Pause for a number of milliseconds" show proper controls (not the generic "Raise UI request" panel); "Get input"/"Show a menu" are gone in favor of the "set variable" template picker; "Ask a question"/"Show a menu" callback forms remain addable; inserted scripts produce the expected literal script text in Code view for each case

🤖 Generated with Claude Code