Rate limit handling seems to be broken: it starts an one-shot timer
with callback that reschedules the timer each second and prints/updates
messages. Simultaneously it schedules a deferred by 1 second function
that cancels the timer and resumes the stream. This results in the timer
executing at most once, and stream resume happening way too early.
Fix this by switching to use repeating timer with first instance
executing immediately. All message handling is moved into the timer
callback. Once countdown is complete the same callback will stop and
destroy the timer and resume the stream.
Move code related to converting history messages into UI representation
from utils into history/render.lua for better code organization and
clean up the implementation.
Code dealing with scanning history messages and extracting some data or
state belongs to avante/history/ so move it there. Along with the move
update the implementation to make use of get_tool_use_data() and
get_tool_result_data() helpers to simplify it.
Also rename the function to History.get_pending_tools() to better
reflect its purpose: "uncalled" means something that was done without
request, unsolicited, not something that has not completed yet.
Simplify the code locating viewed files as well as code locating last
completion attempt by using these new helpers.
Also avoid using "goto" in simple loops.
The utils module has grown too big and contains unrelated functionality.
Start moving code related to managing history messages comprising chat
history into lua/avante/history module to keep the code more manageable.
