fix(cli): prevent hot reload server from pinning a CPU core (#816)

[lewinpauli]

Description

jaspr serve pins a CPU core at 100% even while completely idle (#816).

The generated server_target.dart created the HotReloader with
debounceInterval: Duration.zero. The hotreloader package reuses that value
as the pollingDelay for any watcher that falls back to polling — notably for
watch paths that don't exist, such as an unused bin/ or test/ directory.
With a zero delay this becomes a tight busy loop that pins a CPU core, on every
platform. Most Jaspr projects have neither bin/ nor test/, so two such
watchers spin indefinitely.

This PR:

• Uses a non-zero debounceInterval (200ms) in the generated entrypoint, so any
  polling fallback no longer busy-loops. This alone fixes the reported issue.
• (Optional optimization) Additionally passes excludedPaths for bin/test
  when those folders are absent, so no polling watcher is created for them in the
  first place. Not strictly required once the above is in place — happy to drop
  it if you prefer a more minimal change.

Type of Change

• 🛠️ Bug fix

Ready Checklist

• I've read the Contribution Guide.
• In case this PR changes one of the core packages, I've modified the respective CHANGELOG.md file using the semantic_changelog format.
• I updated/added relevant documentation (doc comments with ///).
• I added myself to the AUTHORS file (optional, if you want to).

[docs-page]

To preview the documentation for this pull request, visit the following URL:

docs.jaspr.site/~825

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[github-actions]

Package Version Report

The following packages have been updated:
jaspr_test : 0.23.1 -> 0.23.2
jaspr : 0.23.1 -> 0.23.2
jaspr_builder : 0.23.1 -> 0.23.2
jaspr_cli : 0.23.1 -> 0.23.2

[schultek]

Thanks for this fix.

Regarding excludePaths, the hotreloader docs say:

[excludedPaths] are always relative to the project's root directory. If the project is a pub workspace, the bin folder of the package will be located in the packages/<package> folder. That means it should be specified like packages/<package>/bin in [excludedPaths], where <package> is the name of the package where the HotReloader is created. If the project consists of a single package, the bin directory lies in the project's root folder and should be specified like bin in [excludedPaths].

So we would have to have a more complex setup for these paths to detect if jaspr is run in a workspace or not.

To avoid that let's just drop the excluded paths, since you said the debounce duration already fixes it. I'm also ok with setting this higher, e.g. 1 second which is the default value.