docs(realtime): use table-scoped postgres channels

[tkkhq]

Tracking

• Tracks: https://konghq.atlassian.net/browse/VOL-1006
• Related: https://konghq.atlassian.net/browse/VOL-1010
• Related: https://github.com/Kong/volcano-hosting/pull/1215
• Related: fix(realtime): send database and presence state volcano-sdk-js#150

Why

• current Hosting and SDK contracts scope each Postgres channel to one database, schema, and table
• end-user subscriptions do not receive DELETE events, so active ordered views need bounded authoritative reconciliation
• asynchronous setup and teardown must not leave stale rows, late state updates, or active clients

Summary

• use one schema:table channel per table with an explicit databaseName
• mark DELETE callbacks as service-key only and use immediate focus plus 30-second authoritative reconciliation for end-user views
• coalesce INSERT and UPDATE events into confirming snapshots instead of applying event records to ordered, capped state
• stop timers, ignore late work, and clean up React connect or subscribe failures before reporting them
• execute the Markdown examples in a regression harness

Verification

• node scripts/check-realtime-example.mjs

• node scripts/check-skills.mjs

• git diff --check

• Prior CI

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