fix(AppShell): resolve custom Included Library content on reload

[alexwarren]

Summary

• Fixes a bug where adding a custom Included Library in the editor, saving, and reopening the game failed with Failed to load game due to the following errors: * Error: Library file not found: lib.aslx — reproducible in both the browser and Electron.
• Also fixes the same error message rendering as a single squashed line (no visible bullet/line breaks) on the editor's Open/reload screens.

Root cause

An Included Library element only stores its filename on save (<include ref="lib.aslx"/> — see IncludeSaver), not its content. The engine re-fetches the library's content from IGameDataProvider.GetAdjacentFile on every load (WorldModel.GetLibraryStream). WasmEditorBridge always loaded games through ByteArrayGameDataProvider, which had no GetAdjacentFile implementation at all, so any non-built-in library failed to resolve as soon as the game was reloaded — even though the library file was correctly stored as an asset and shown in the tree.

(Published .quest packages aren't affected — GameSaver inlines all library content and drops the <include> reference at publish time, so there's nothing left to resolve at play time. This is specific to the Editor's live-reference save mode.)

Fix

• ByteArrayGameDataProvider now accepts an optional adjacentFiles map and implements GetAdjacentFile from it.
• WasmEditorBridge gets a new AddAdjacentFile JSExport (mirrors the existing AddPublishAsset staging pattern); Initialise/SetGameXml consume the staged files when building the provider.
• editor-store.ts preloads every .aslx asset from the adapter before Initialise/SetGameXml — this is a single choke point so it covers browser, Electron, and server storage.

Separately: the multi-line "Failed to load game due to the following errors:" message was collapsing onto one line in the UI because the <p> tags rendering it had no white-space styling — CodeViewPanel.svelte's equivalent error banner already used whitespace-pre-wrap, so the same class was added to the other three render sites (open/+page.svelte ×2, edit/+page.svelte).

Test plan

• Added two regression tests to IncludedLibraryTests.cs (reload fails without adjacent bytes, succeeds with them) — reproduces the exact reported error message.
• dotnet build --configuration Release (full solution) and dotnet test --configuration Release (292+ tests) both pass.
• npm run check (svelte-check) and npm run lint (eslint) in src/AppShell both pass.
• Verified live in the AppShell dev server: created a game, added a custom library, saved, reloaded — previously failed, now loads correctly.
• Verified the error-formatting fix live by importing a game with a broken library reference and confirming the message now renders on separate lines instead of squashed onto one.

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