fix(markdown): support underscore emphasis near punctuation

[rebelchris]

Summary

• Adjust markdown-it underscore delimiter scanning so single _ can open or close emphasis at word-to-punctuation boundaries.
• Preserve intraword underscore protection for snake_case, code spans, linkified URLs, and __ strong emphasis.
• Add focused markdown renderer coverage for the reported patterns and non-regression cases.

Verification

• NODE_ENV=test npx pnpm@10.33.4 exec jest __tests__/common/markdown.ts --testEnvironment=node --runInBand
• npx pnpm@10.33.4 exec eslint src/common/markdown.ts __tests__/common/markdown.ts --max-warnings 0
• npx pnpm@10.33.4 run build

Closes ENG-1645

---

Created by Huginn 🐦‍⬛

[pulumi]

🍹 The Update (preview) for dailydotdev/api/prod (at c0a71f4) was successful.

✨ Neo Code Review

Routine deployment of a new application version (`bd8bfc4d`) containing a markdown rendering fix for underscore emphasis around punctuation. ✅ Low Risk

This is a standard application deployment rolling out commit bd8bfc4d to replace b9667bb5. All deployment and cron job updates are purely image tag and version label bumps. The migration Jobs (Postgres and Clickhouse) are recycled per-commit as designed — old Jobs are deleted and new ones created with the new image, which will run migrations against the database before traffic shifts.

The GCP credentials warning is unrelated to this deployment and does not affect the Kubernetes operations.

Resource Changes

    Name                                                       Type                           Operation
~   vpc-native-update-highlighted-views-cron                   kubernetes:batch/v1:CronJob    update
~   vpc-native-expire-super-agent-trial-cron                   kubernetes:batch/v1:CronJob    update
~   vpc-native-update-tag-materialized-views-cron              kubernetes:batch/v1:CronJob    update
~   vpc-native-post-lifecycle-state-clickhouse-cron            kubernetes:batch/v1:CronJob    update
~   vpc-native-materialize-monthly-best-post-archives-cron     kubernetes:batch/v1:CronJob    update
~   vpc-native-user-posts-analytics-refresh-cron               kubernetes:batch/v1:CronJob    update
+   vpc-native-api-clickhouse-migration-bd8bfc4d               kubernetes:batch/v1:Job        create
~   vpc-native-squad-posts-analytics-refresh-cron              kubernetes:batch/v1:CronJob    update
~   vpc-native-post-analytics-clickhouse-cron                  kubernetes:batch/v1:CronJob    update
~   vpc-native-user-profile-updated-sync-cron                  kubernetes:batch/v1:CronJob    update
~   vpc-native-channel-highlights-cron                         kubernetes:batch/v1:CronJob    update
-   vpc-native-api-db-migration-b9667bb5                       kubernetes:batch/v1:Job        delete
~   vpc-native-worker-job-deployment                           kubernetes:apps/v1:Deployment  update
~   vpc-native-hourly-notification-cron                        kubernetes:batch/v1:CronJob    update
~   vpc-native-user-profile-analytics-history-clickhouse-cron  kubernetes:batch/v1:CronJob    update
~   vpc-native-update-trending-cron                            kubernetes:batch/v1:CronJob    update
~   vpc-native-update-current-streak-cron                      kubernetes:batch/v1:CronJob    update
~   vpc-native-update-source-public-threshold-cron             kubernetes:batch/v1:CronJob    update
~   vpc-native-clean-channel-highlights-cron                   kubernetes:batch/v1:CronJob    update
~   vpc-native-deployment                                      kubernetes:apps/v1:Deployment  update
~   vpc-native-user-profile-analytics-clickhouse-cron          kubernetes:batch/v1:CronJob    update
~   vpc-native-post-analytics-history-day-clickhouse-cron      kubernetes:batch/v1:CronJob    update
~   vpc-native-bg-deployment                                   kubernetes:apps/v1:Deployment  update
~   vpc-native-generic-referral-reminder-cron                  kubernetes:batch/v1:CronJob    update
~   vpc-native-rotate-weekly-quests-cron                       kubernetes:batch/v1:CronJob    update
-   vpc-native-api-clickhouse-migration-b9667bb5               kubernetes:batch/v1:Job        delete
~   vpc-native-channel-digests-cron                            kubernetes:batch/v1:CronJob    update
~   vpc-native-clean-zombie-users-cron                         kubernetes:batch/v1:CronJob    update
~   vpc-native-temporal-deployment                             kubernetes:apps/v1:Deployment  update
~   vpc-native-personalized-digest-deployment                  kubernetes:apps/v1:Deployment  update
~   vpc-native-personalized-digest-cron                        kubernetes:batch/v1:CronJob    update
~   vpc-native-check-analytics-report-cron                     kubernetes:batch/v1:CronJob    update
~   vpc-native-sync-subscription-with-cio-cron                 kubernetes:batch/v1:CronJob    update
~   vpc-native-clean-stale-user-transactions-cron              kubernetes:batch/v1:CronJob    update
~   vpc-native-generate-search-invites-cron                    kubernetes:batch/v1:CronJob    update
~   vpc-native-rotate-daily-quests-cron                        kubernetes:batch/v1:CronJob    update
~   vpc-native-clean-zombie-opportunities-cron                 kubernetes:batch/v1:CronJob    update
~   vpc-native-clean-zombie-user-companies-cron                kubernetes:batch/v1:CronJob    update
~   vpc-native-calculate-top-readers-cron                      kubernetes:batch/v1:CronJob    update
~   vpc-native-materialize-yearly-best-post-archives-cron      kubernetes:batch/v1:CronJob    update
~   vpc-native-update-views-cron                               kubernetes:batch/v1:CronJob    update
... and 13 other changes