feat: add invitation functionality and email integration (#1942)

* feat: add invitation functionality and email integration

- Introduced `invitationRouter` for managing project invitations, including listing, creating, accepting, and deleting invitations.
- Updated `project_invitations` schema to enforce unique constraints on invitee email and project ID.
- Implemented email sending capabilities using Resend for invitation notifications.
- Added new email templates for user invitations.
- Updated environment variables to include `RESEND_API_KEY` for email service integration.
- Refactored related components and API routes to accommodate new invitation features.
- Created migration to drop the `status` column from `project_invitations` and enforce unique constraints.

Author: satya-nutella

.gitignore

@@ -41,4 +41,6 @@ yarn.lock
 .env.local
 .env.development.local
 .env.test.local
-.env.production.local
+.env.production.local
+
+mise.toml

apps/backend/supabase/migrations/0005_short_lila_cheney.sql

@@ -0,0 +1,3 @@
+ALTER TABLE "project_invitations" DROP COLUMN "status";--> statement-breakpoint
+ALTER TABLE "project_invitations" ADD CONSTRAINT "project_invitations_invitee_email_project_id_unique" UNIQUE("invitee_email","project_id");--> statement-breakpoint
+DROP TYPE "public"."invitation_status";