[WC-3452] Add pusher module to the repo

[r0b1n]

This adds pusher module to the repo, has old widget as an asses to copy into the module.

[github-actions]

AI Code Review

🔶 Changes requested — one or more medium-severity items must be addressed

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What was reviewed

File	Change
packages/pluggableWidgets/pusher-web/src/Pusher.tsx	Refactored to multi-handler event binding via eventHandlers list
packages/pluggableWidgets/pusher-web/src/Pusher.xml	Replaced notifyActionName/notifyEventAction with eventHandlers list object
packages/pluggableWidgets/pusher-web/src/Pusher.editorConfig.ts	Added check() for duplicate action names; updated getCaption()
packages/pluggableWidgets/pusher-web/src/utils/PusherListener.ts	Reworked to bind_global + eventHandlersMap; channel-level rebind optimization
packages/pluggableWidgets/pusher-web/src/utils/getChannelName.ts	Removed unsafe cast
packages/pluggableWidgets/pusher-web/typings/PusherProps.d.ts	Updated typings: objectSource → DynamicValue<ObjectItem>, added EventHandlersType
packages/pluggableWidgets/pusher-web/CHANGELOG.md	No entry for this breaking change (widget behavior changed)
packages/modules/pusher/	New module scaffold (package.json, scripts, CHANGELOG, LICENSE)
packages/pluggableWidgets/pusher-web/package.json	Version bump 2.0.0 → 4.0.0

Skipped (out of scope): pnpm-lock.yaml, binary PNG assets

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Findings

🔶 Medium — No CHANGELOG entry for breaking API change

File: packages/pluggableWidgets/pusher-web/CHANGELOG.md
Problem: The XML schema changed (removed notifyActionName + notifyEventAction, added eventHandlers list) and PusherContainerProps changed (objectSource type changed from ListValue to DynamicValue<ObjectItem>). This is a breaking change for existing widget users and requires a changelog entry per repo conventions.
Fix: Add an entry under [Unreleased] describing the breaking change, e.g.:

### Changed

- Replaced single `notifyActionName`/`notifyEventAction` properties with a configurable `eventHandlers` list, enabling multiple event bindings per widget instance. **Breaking:** existing widget configurations must be migrated.
- Changed `objectSource` from a list datasource to a single-object datasource.

Run pnpm -w changelog to open the guided prompt if available.

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🔶 Medium — Placeholder test file — no real coverage for changed logic

File: packages/pluggableWidgets/pusher-web/src/__tests__/Pusher.spec.tsx
Problem: The test file contains only a passing placeholder (expect(true).toBe(true)) with a TODO comment. The PR introduces substantial new logic: multi-handler binding, usePusherSubscribe hook lifecycle, PusherListener channel-change optimisation, and check() in editorConfig. None of this is covered.
Fix: At minimum, add unit tests for:

• PusherListener.subscribe() — verifies bind_global is called once per channel and eventHandlersMap is updated on re-subscription without a channel rebind.
• check() in editorConfig — verifies duplicate actionName produces an error, unique names produce none.
• Pusher component — renders the div, calls executeAction when the relevant event fires.

Use @mendix/widget-plugin-test-utils builders for Mendix data mocking, e.g.:

import { EditableValueBuilder } from "@mendix/widget-plugin-test-utils";

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🔶 Medium — objectSource status not checked before dereferencing .value

File: packages/pluggableWidgets/pusher-web/src/utils/getChannelName.ts line 4
Problem: objectSource.value is accessed directly without checking objectSource.status. When status is "loading" or "unavailable", .value is undefined, which the if (!object) guard handles — but this can mask a genuine unavailability and cause a silent no-subscribe silently indefinitely. Mendix conventions require checking .status before reading .value from DynamicValue.
Fix:

export function getChannelName(objectSource: DynamicValue<ObjectItem>): string | undefined {
    if (objectSource.status !== "available") {
        return undefined;
    }
    const object = objectSource.value;
    // ... rest unchanged
}

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⚠️ Low — useMemo over mutable eventHandlers array causes spurious re-subscriptions

File: packages/pluggableWidgets/pusher-web/src/Pusher.tsx line 45
Note: eventHandlers is a new array reference on every render (Mendix re-creates list prop arrays), so useMemo([channelName, eventHandlers, handleError]) will recompute on every render even if handler contents haven't changed. PusherListener.subscribe() handles this gracefully (skips re-subscription if channelName is the same), but the subscription object reference changes every render, causing the useEffect in usePusherSubscribe to call unsubscribe/subscribe on each render. Consider stabilizing the eventHandlers reference, or memoizing per-handler identity, to avoid churn.

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⚠️ Low — extractEntityName uses unsafe symbol-based internal API access

File: packages/pluggableWidgets/pusher-web/src/utils/getChannelName.ts line 22
Note: (object as any)[Object.getOwnPropertySymbols(object)[0]] accesses an internal property via the first Symbol key. This is fragile — symbol order is not guaranteed across Mendix runtime versions, and the approach bypasses TypeScript safety. Consider using a supported Mendix API to get the entity name (e.g. via mx.meta.getMetaObject), or document the risk with a comment referencing the specific Mendix version where this is known to work.

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⚠️ Low — action not guarded with canExecute before calling executeAction

File: packages/pluggableWidgets/pusher-web/src/Pusher.tsx line 31
Note: executeAction(handler.action) calls the helper without checking handler.action?.canExecute. executeAction from @mendix/widget-plugin-platform likely guards this internally, but per repo conventions (AGENTS.md: "Check ActionValue.canExecute before execute()") the explicit check should be visible at the call site to avoid ambiguity.

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Positives

• The bind_global + eventHandlersMap pattern is a clean optimization: channel subscriptions are only torn down when the channel name changes, not on every handler update — this avoids Pusher re-auth overhead.
• The check() function in editorConfig correctly detects duplicate actionName entries at design-time in Studio Pro before runtime, which is a great DX improvement.
• The AbortController pattern in usePusherSubscribe properly guards against state updates after unmount.
• Removing the // TODO: fix typings cast in getChannelName.ts and the ListValue → DynamicValue<ObjectItem> correction are clean type-safety improvements.
• The module scaffold in packages/modules/pusher/ follows the existing module pattern (compare web-actions) faithfully.

[iobuhov]

LGTM