Improve platform detection and compatibility with PieFed 1.2

[hjiangsu]

Pull Request Description

This PR contains the following changes:

• detectPlatformFromNodeInfo now returns back the platform (e.g., Lemmy/PieFed) and the associated version. The version is stored within a temporary cache PlatformVersionCache to allow other parts of Thunder to quickly determine the version for a given instance.
• Cleaned up unused attributes within the various Thunder internal models. We can re-introduce these attributes once they're needed. Removing these attributes helps simplify the translation from Lemmy/PieFed responses to the internal models.
• Updated PieFed APIs to support the upcoming 1.2 version. As a result of this, I've also refactored the comment fetching logic to make it easier to work with.

Other miscellaneous changes:

• Removed delays from profile switching as it's no longer necessary
• Added debug flags to various places to turn on/off debug messages
• Fixed an issue where Thunder would crash when image dimension caching was done within an isolate
• Updated the post page such that the post shows up immediately when navigating to it from the feed

Issue Being Fixed

Issue Number: N/A

Screenshots / Recordings

Checklist

• If a new package was added, did you ensure it uses an appropriate license and is actively maintained?
• Did you use localized strings (and added appropriate descriptions) where applicable?
• Did you add semanticLabels where applicable for accessibility?