fix(reactivity): Prevent TypeError in wineCtx due to non-atomic property access

[sentry]

Summary

This PR addresses issue RUST-G, a TypeError: undefined is not an object (evaluating 'game.runtime.runtime') originating from the wineCtx function in src/lib/types.ts. The fix involves caching the result of game?.runtime into a local variable (r) immediately after the initial check. This ensures that both the existence check (if (!r)) and the subsequent property access (r.runtime === 'wine') operate on the same, stable value, thereby eliminating the race condition caused by Svelte's reactivity and preventing the TypeError.

Changes

• Modified the wineCtx function in src/lib/types.ts to use an atomic pattern for accessing game.runtime.
• Introduced a local variable to cache the result of game?.runtime to prevent race conditions in Svelte 5 reactive contexts (e.g., $derived in src/routes/+page.svelte).

Testing

• cargo test -p corkscrew passes
• npx svelte-check --threshold error passes
• Manually tested with cargo tauri dev (if UI changes)

Notes

Root Cause:
The wineCtx function (lines 114-115) had a non-atomic pattern for accessing game.runtime. It first checked if (!game?.runtime) and then, in the subsequent line, accessed game.runtime.runtime. When wineCtx is called from a Svelte 5 reactive context (e.g., a $derived in src/routes/+page.svelte), game is a reactive Proxy. Between the initial nullish check and the second property access, Svelte's reactivity system could re-evaluate game.runtime, causing it to become undefined and leading to the TypeError.

Solution:
The fix involves caching the result of game?.runtime into a local variable (r) immediately after the initial check. This ensures that both the existence check (if (!r)) and the subsequent property access (r.runtime === 'wine') operate on the same, stable value, thereby eliminating the race condition caused by Svelte's reactivity and preventing the TypeError.

Fixes RUST-G