Fix Linux Steam game detection

[halgari]

Summary

Vortex cannot discover Steam games on Linux due to two independent bugs:

1. Steam path detection uses getVortexPath("home") instead of os.homedir() — prevents the Steam base directory from being found at all.
2. GameStoreHelper.find() regression — a strictNullChecks refactor broke all queryArgs-based game discovery.

Bug 1: Wrong home directory from Electron initialization dependency

getLinuxSteamPaths() called getVortexPath("home") to build paths like ~/.local/share/Steam. Under the hood, getVortexPath("home") resolves through a multi-layered system that depends on Electron's initialization state:

• Main process: delegates to electron.app.getPath("home") via cachedAppPath(), which requires the Electron app object to be fully initialized. If app is undefined (e.g. the call happens before Electron is ready, or in a forked child process that didn't receive the env vars), it falls back to os.tmpdir() — returning something like /tmp instead of the user's home directory.
• Renderer process: reads from ApplicationData.vortexPaths, a cache populated over IPC from the main process during startup. If the cache hasn't been populated yet (timing-dependent), the path lookup can fail or return stale/incorrect values.
• Forked child processes: read from environment variables (ELECTRON_HOME) that are set when the process is spawned. If game discovery runs in a context where these env vars weren't propagated, the home path is wrong.

All of these indirections are unnecessary here. The home directory is a simple OS-level fact — os.homedir() returns it directly from Node.js without any dependency on Electron's lifecycle, IPC state, or environment variable propagation. The fix replaces getVortexPath("home") with os.homedir().

Bug 2: GameStoreHelper.find() always discards results

Commit f4d9f06 (a strictNullChecks refactor) changed the guard in find() from:

if (result !== undefined)

to:

if (result && result.gameStoreId !== undefined && result.priority !== undefined)

The result.priority !== undefined check is the problem: priority is not a field that game stores set on their entries — it's assigned inside this very block. The old code checked result !== undefined, then assigned priority. The refactored code checks priority as a precondition, which always fails, so every result is silently discarded. This breaks all queryArgs-based discovery (the primary mechanism game extensions use to find installed games).

The fix restores the guard to if (result !== undefined) and keeps strict null safety by wrapping the mStoresDict lookup in a ternary to handle entries where gameStoreId is undefined (registry entries).

Test plan

• yarn build compiles without errors in modified files
• yarn test — no test regressions from these changes
• Manual: start Vortex on Linux, verify Steam games are automatically discovered

[halgari]

not sure if the os.homedir() thing is really what we want, considering the IPC separation, but this fixes the game detection for linux which has been broken since the IPC changes went in.

[Empty-Ghost]

Fix Linux game detection

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