[AlexAndBear]

Description

• Not found instead of Personal: a project/ link that matches none of your spaces now shows "Resource not found" with a button to the Spaces overview. Before, DriveRedirect silently sent you to your Personal files.
• Other redirects unchanged: the empty alias, personal/home and other personal links, users without a personal space and guests still redirect like before.
• Leaving the page: the redirect now follows alias changes, so going to Personal, Spaces or the logo from the not found page works (the component stays mounted while no space matches).

Related Issue

• Fixes A link to a space you no longer have access to silently opens your Personal files #3950

How Has This Been Tested?

• test environment: unit tests (Vitest), browser tests (Playwright) against a local OpenCloud
• test case 1: unit: unknown project alias shows the message without redirect; personal/home, empty alias, guest and no personal space still redirect once; navigating from the message to personal redirects; NotFoundMessage shows the Spaces button for an unknown project alias
• test case 2: browser: reproduced on main (Personal opened silently for a removed space, a made-up space and a folder link), fixed on this branch; sidebar, logo, back/forward from the message; member spaces, renamed spaces via fileId, space trash and personal links still open; no not found flash while loading (delayed responses); Pixel 7

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)