feat: add /og contextual share-image route

[rebelchris]

What

Adds a /og/:type/:name.png route that renders the webapp's contextual share-card pages and screenshots them via the scraper — the same pipeline as the DevCard v2 image (/devcards/v2), no Satori.

Backs the webapp PR: dailydotdev/apps#6243.

How

• New src/routes/shareImages.ts: one generic handler over an allowlist of types (posts, comments, sources, squads, profile, tags, invite, plus). Builds ${COMMENTS_PREFIX}${WEBAPP_MAGIC_IMAGE_PREFIX}/share/<type>/<id>, POSTs { url, selector: '#screenshot_wrapper' } to SCRAPER_URL/screenshot, and streams the PNG with cache-control: public, max-age=3600, s-maxage=3600 + COOP/CORP headers (mirrors devcards v2).
• Forwards ?userid for share attribution (post/squad "shared by / invited you").
• Registered at /og in src/routes/index.ts.

Test plan

• GET /og/posts/<id>.png (and ?userid=<userId>)
• GET /og/{comments,sources,squads,profile,tags,invite,plus}/<id>.png
• Unknown type or missing .png → 404.

🤖 Generated with Claude Code

[pulumi]

🍹 The Update (preview) for dailydotdev/api/prod (at 3bef5c1) was successful.

Resource Changes

    Name                                                       Type                           Operation
~   vpc-native-check-analytics-report-cron                     kubernetes:batch/v1:CronJob    update
~   vpc-native-user-profile-analytics-history-clickhouse-cron  kubernetes:batch/v1:CronJob    update
~   vpc-native-expire-super-agent-trial-cron                   kubernetes:batch/v1:CronJob    update
+   vpc-native-api-clickhouse-migration-9e3f27d6               kubernetes:batch/v1:Job        create
~   vpc-native-calculate-top-readers-cron                      kubernetes:batch/v1:CronJob    update
~   vpc-native-validate-active-users-cron                      kubernetes:batch/v1:CronJob    update
~   vpc-native-update-tag-materialized-views-cron              kubernetes:batch/v1:CronJob    update
~   vpc-native-rotate-weekly-quests-cron                       kubernetes:batch/v1:CronJob    update
-   vpc-native-api-clickhouse-migration-03f7fbd4               kubernetes:batch/v1:Job        delete
~   vpc-native-squad-posts-analytics-refresh-cron              kubernetes:batch/v1:CronJob    update
~   vpc-native-clean-channel-highlights-cron                   kubernetes:batch/v1:CronJob    update
~   vpc-native-clean-zombie-images-cron                        kubernetes:batch/v1:CronJob    update
~   vpc-native-post-analytics-clickhouse-cron                  kubernetes:batch/v1:CronJob    update
~   vpc-native-clean-old-notifications-cron                    kubernetes:batch/v1:CronJob    update
~   vpc-native-update-current-streak-cron                      kubernetes:batch/v1:CronJob    update
~   vpc-native-materialize-yearly-best-post-archives-cron      kubernetes:batch/v1:CronJob    update
~   vpc-native-clean-zombie-users-cron                         kubernetes:batch/v1:CronJob    update
~   vpc-native-post-analytics-history-day-clickhouse-cron      kubernetes:batch/v1:CronJob    update
~   vpc-native-personalized-digest-deployment                  kubernetes:apps/v1:Deployment  update
~   vpc-native-update-tags-str-cron                            kubernetes:batch/v1:CronJob    update
~   vpc-native-private-deployment                              kubernetes:apps/v1:Deployment  update
~   vpc-native-update-source-public-threshold-cron             kubernetes:batch/v1:CronJob    update
~   vpc-native-temporal-deployment                             kubernetes:apps/v1:Deployment  update
~   vpc-native-update-achievement-rarity-cron                  kubernetes:batch/v1:CronJob    update
~   vpc-native-clean-zombie-opportunities-cron                 kubernetes:batch/v1:CronJob    update
~   vpc-native-generate-search-invites-cron                    kubernetes:batch/v1:CronJob    update
~   vpc-native-worker-job-deployment                           kubernetes:apps/v1:Deployment  update
~   vpc-native-personalized-digest-cron                        kubernetes:batch/v1:CronJob    update
~   vpc-native-generic-referral-reminder-cron                  kubernetes:batch/v1:CronJob    update
~   vpc-native-bg-deployment                                   kubernetes:apps/v1:Deployment  update
-   vpc-native-api-db-migration-03f7fbd4                       kubernetes:batch/v1:Job        delete
~   vpc-native-rotate-daily-quests-cron                        kubernetes:batch/v1:CronJob    update
~   vpc-native-clean-zombie-user-companies-cron                kubernetes:batch/v1:CronJob    update
~   vpc-native-channel-highlights-cron                         kubernetes:batch/v1:CronJob    update
~   vpc-native-hourly-notification-cron                        kubernetes:batch/v1:CronJob    update
~   vpc-native-daily-digest-cron                               kubernetes:batch/v1:CronJob    update
~   vpc-native-clean-gifted-plus-cron                          kubernetes:batch/v1:CronJob    update
~   vpc-native-user-profile-updated-sync-cron                  kubernetes:batch/v1:CronJob    update
~   vpc-native-ws-deployment                                   kubernetes:apps/v1:Deployment  update
~   vpc-native-post-analytics-achievements-cron                kubernetes:batch/v1:CronJob    update
~   vpc-native-update-highlighted-views-cron                   kubernetes:batch/v1:CronJob    update
... and 14 other changes