feat: improved public API + documentation for self hosting

Author: Rieranthony

apps/api/drizzle/migrations/0058_dazzling_bedlam.sql

@@ -0,0 +1,3 @@
+ALTER TABLE "api_key" ADD COLUMN "linked_user_id" varchar(26);--> statement-breakpoint
+ALTER TABLE "api_key" ADD CONSTRAINT "api_key_linked_user_id_user_id_fk" FOREIGN KEY ("linked_user_id") REFERENCES "public"."user"("id") ON DELETE set null ON UPDATE no action;--> statement-breakpoint
+CREATE INDEX "api_key_linked_user_idx" ON "api_key" USING btree ("linked_user_id");

apps/api/drizzle/migrations/0059_slippery_the_renegades.sql

@@ -0,0 +1 @@
+ALTER TABLE "conversation" ADD COLUMN "metadata" jsonb;