Replace the SSM Parameters section with the new Secrets Manager secret
structure (3 grouped secrets) and correct the runtime-config note.
Refs: INFRA-5, #3
* Merge expense-approval-bot into payments-dashboard
Port the Slack reaction-driven expense routing workflow (receiver +
processor) from expense-approval-bot into this stack as JavaScript ESM.
Secrets copied to payments-dashboard/ prefix in Secrets Manager.
* Fix review findings from PR #28
- Add length check before timingSafeEqual to prevent RangeError on
malformed signatures (returns 401 instead of 500)
- Check event.type === reaction_added to prevent reaction_removed
from advancing expenses
- Move getPermalink call behind isOrigin check to skip unnecessary
API call on non-origin stage transitions
- Add OAuth client-credentials token exchange to both Lambda handlers
- Fix sandbox/prod base URL (api-sb.bofa.com / api.bofa.com)
- Fix issueAction casing to add_Issue / cancel_Issue per API docs
- Fix transaction inquiry response parsing (accountTransactions array)
- Move all BoA config (app IDs, bank ID) from env vars to SSM params
- Update template.yaml with correct SSM param names and policies
- Add project README with architecture, API details, and SSM param reference
