fix issue #5075

[RyuDanuer]

Brief Description of What This PR Does

-Added robust scene loading with retries + cache bypass on retries (ResourceLoader.CacheMode.Ignore) in SceneLoadHelpers.cs.
-Updated scene transitions to use that helper and fail fast if all attempts fail
-Hardened Thriveopedia page creation so random scene instantiate failures don’t crash/load into broken state

Related Issues

Progress Checklist

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[hhyyrylainen]

I think something pretty strange has happened here with git as all of the files show as being totally new and not modified existing files.

[hhyyrylainen]

Related to the retry logic etc. I think that is sadly kind of a misplaced attempt, because the Godot Engine just flat out gives up at some point and no further scene loads ever work correctly. So we cannot do a workaround like this, because to actually get out of the buggy state we would have to get the entire game process restarted. And adding logic that maybe works around a few cases would mean that every single place in the game would need the same kind of retry, because if one scene fails and it is worked around the engine will just blow up in the next scene load that isn't guarded.