Fix dictionary change update issues / seamlessness

[YKawesome]

Summary

Currently dictionary rebuilds are not reliably handled by existing profiles. This required a bit of a dance to get the profile to register the updated dictionary. This PR makes the auto-reload robust/reliable using a stable id to refresh the backend registry.

Changes

• fprime/src/dictionary/index.ts
  • Adds a 500ms debounce so a build write becomes a single reload
  • Dedupe discovered dictionaries by deployment name with latest file modification time winning (skips files without a name/id)
  • Cleanly cancels any pending timer on dispose
• core/src/context.ts
  • Serialize reloads per provider so concurrent file events are not interleaved and the last one wins
  • Add/update discovered dictionaries and then remove ids only if not present
  • Any still-referenced ids are not removed even if there is a failure in the current update

Note

You'll still have to use the start/stop element of the profile to pick up the changes (that was the original issue) but if desired I could see about updating it to automatically pick up the changes.

Issues

Closes #169

[YKawesome]

@Kronos3 could you let me know if this fixes your issue?