[AlexAndBear]

Description

Opening an app URL for a space you can't see, or the bare app route without a file, now shows the regular "Resource not found" screen instead of a raw JavaScript error, the same as for a file that doesn't exist.

Related Issue

• Fixes Opening an app URL for a space you can't access shows a raw JavaScript error and no way to close the app #4255

How Has This Been Tested?

• test environment: unit tests (Vitest), browser tests (Playwright) against a local OpenCloud
• test case 1: unit: unknown space and app route without a file show the not found screen without loading the file
• test case 2: unit: drive alias recovery still works when the space only resolves after the route update
• test case 3: browser: unknown project space, another user's personal space (shared and not shared) and /text-editor show the not found screen, desktop and Pixel 7
• test case 4: browser: opening files from the list, permanent links, fileId without drive alias, received shares, public links and the preview 404 still work

Types of changes

• Bugfix
• Enhancement (a change that doesn't break existing code or deployments)
• Breaking change (a modification that affects current functionality)
• Technical debt (addressing code that needs refactoring or improvements)
• Tests (adding or improving tests)
• Documentation (updates or additions to documentation)
• Maintenance (like dependency updates or tooling adjustments)