refactor(cdp): rename emailAssets to messageAssets

[dmarchuk]

Problem

CyclotronJobInvocationResult.emailAssets now carries push rows as well as email ones. #74555 called this out as the one place the reuse leaks and left the rename out to keep that diff reviewable:

The one place reuse leaks is the field still called emailAssets on the invocation result, which now carries push rows too; renaming it to messageAssets is a mechanical follow-up left out to keep this diff reviewable.

This is that follow-up. The underlying table, service and row type are already channel-agnostic (message_assets, MessageAssetsService, MessageAssetRow), so the field name was the last thing still claiming email.

Changes

Pure rename, emailAssets to messageAssets, across 17 files. No behavior change: the field is renamed at its declaration, at every producer and consumer, and in the tests.

messageAssetsService (the service handle on PushNotificationService and EmailService) is a different identifier and is untouched.

How did you test this code?

Mechanical, so the check is that nothing else moved:

• 0 occurrences of emailAssets remain in nodejs/src; 56 of messageAssets.
• tsc --noEmit adds no new errors versus the base branch. Both report the same 7 pre-existing @posthog/replay-anonymizer module-resolution errors from an unbuilt local package.
• jest src/cdp/services/messaging src/cdp/services/hogflows src/cdp/utils - 658 passing. The 2 failures are the maildev-backed email tests, which fail identically on the base branch without a maildev container and pass in CI.

No test was added: a rename with no behavior change has no regression to catch that the type checker doesn't already catch.

Automatic notifications

• Publish to changelog?
• Alert Sales and Marketing teams?

Docs update

None needed. The field is internal to the invocation result and not part of any documented surface.

🤖 Agent context

Autonomy: Human-driven (agent-assisted). Directed by @dmarchuk, assigned as DRI.

Stacked on #75800, which is stacked on #74555. Kept last in the stack deliberately: a mechanical sweep should come after the semantic changes so it picks them up, rather than forcing them to rebase across a rename.

[greptile-apps]

_{Reviews (1): Last reviewed commit: "refactor(cdp): rename emailAssets to mes..." | Re-trigger Greptile}