Enhancement: Add temporary achievement progress

Currently there are two ways of validating achievements: Either the achievement's progress is saved, or the achievement's progress is transient. For transient achievements, the progress bar doesn't show up.

Edit the transient acheivements checking function and associated data so that a progress bar for the acheivements shows up.

No files are listed, so first search the codebase for the transient achievement-checking logic and where achievement progress bars are rendered in the UI. Then inspect the data model used for saved achievement progress and align transient achievement data so it can be rendered similarly. Run the achievement-related flow (or tests, if present) and confirm transient achievements now show a visible progress bar and still behave like existing progress bars for normal achievements.

Vom Indexierungsmodell aus dem Issue-Text verfasst.