fix(amazonq): Improve indexing auto start-stop strategy

[leigaol]

Problem

When multiple IDE instances are opened at the same time, the @workspace indexing can increase CPU usage to a point that system fan needs to engage. IDE can be slow if it is older devices like intel i5 or i7 Mac OS.

Solution

When multiple IDE instances are opened at the same time, the @workspace indexing can increase CPU usage to a point that system fan needs to engage. IDE can be slow if it is older devices like intel i5 or i7 Mac OS. This PR is to improve indexing auto start-stop strategy, detect CPU usage more frequently and pause indexing more aggressively whenever system total CPU usage goes up. In the mean time, further reduce CPU usage for old Intel i5, i7 devices, make sure one IDE instance at most utilize one physical core and all instance combined cannot exceed 1 for any extended period of time more than a few seconds, unless user explicit allows more CPU usage in settings. Other mechanisms are implemented to stop indexing if system available memory is small.

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License: I confirm that my contribution is made under the terms of the Apache 2.0 license.

[github-actions]

• This pull request modifies code in src/* but no tests were added/updated.
  • Confirm whether tests should be added or ensure the PR description explains why tests are not required.