[ENHANCE] simplify (refactor) chatStore design

[a7m-1st]

Motivation

Abstract

• In our efforts to organize projects based on chatStore #473 , we introduced a decoupled interface.
• Previously it was chatStore -> tasks[], but now with projectStore it became projectStore -> chatStore[] -> tasks[]

Due to progressive shipping and backwards compatibility, I intentionally didn't touch the chatStore structure. But now perhaps its time to simplify bcz a single chatStore would contain a single task. The old design is absolute.

The bump in the road 🚧

• Before starting modifying the structure take note of the ghost chatStore👻. It is being created somewhere (try to Replay then log the chatStore) due to the old code structure.

Solution

⚠️ First Solve:

• Ghost chatStore must be exterminated ❗

Migrate:

• remove: chatStore.activeTaskId
• tasks[] -> task
• update all chatStore usage of chatStore.tasks[chatStore.activeTaskId] TO chatStore.task
• update some functions in projectStore to use singular task
• simplify all chatStore functions to use a singlar task design

The frontend result

Alternatives

No response

Additional context

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