Adds lifecycle hooks to the base platform adapter so Discord (and future
platforms) can react to message processing events:
👀 when processing starts
✅ on successful completion (delivery confirmed)
❌ on failure, error, or cancellation
Implementation:
- base.py: on_processing_start/on_processing_complete hooks with
_run_processing_hook error isolation wrapper; delivery tracking
via _record_delivery closure for accurate success detection
- discord.py: _add_reaction/_remove_reaction helpers + hook overrides
- Tests for base hook lifecycle and Discord-specific reactions
Co-authored-by: alanwilhelm <alanwilhelm@users.noreply.github.com>
227601c200