refactor: replace the custom client with @gathertown/webhook-object-sdk

[gesposito]

Summary

Removes the hand-rolled packages/client now that the official SDK is on npm, and migrates all four demos to @gathertown/webhook-object-sdk.

• new Client({ url, secret }) → createWebhookObjectClient(...); client.send({ type, timestamp, data }) → client.send(type, data), the SDK stamps timestamps itself, and empty-payload events (counter.reset, activity.clear, …) take no argument.
• Follow-on cleanup: dropped the client-only @vitest/browser*/playwright root devDeps and the CI Playwright install step; removed the undici external from the claude-status bundle (the SDK uses the global fetch); updated the demo READMEs.
• Allow-listed the two first-party packages in minimumReleaseAgeExclude, the 7-day age gate would otherwise block them until a week after each release.

Test plan

• pnpm lint, pnpm -r build, pnpm -r test all green (12 tests)

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Note

Medium Risk
Behavior now depends on an external SDK’s signing, timestamps, and retry semantics instead of the removed in-repo client; webhook delivery changes are possible across all demos.

Overview
Removes the entire packages/client workspace package (client implementation, object types, and its Vitest browser/Playwright test setup) in favor of the published @gathertown/webhook-object-sdk (^0.1.1) and @gathertown/webhook-object-types where types are needed.

All four demos (claude-status, gh-prs-inbox, low-battery-switch, now-playing-inbox) now use createWebhookObjectClient and the SDK’s client.send(eventType, data) API instead of building full { type, timestamp, data } payloads; empty-payload events call send with no second argument. claude-status passes AbortSignal.timeout(3s) on the client so the whole send (including retries) is capped. Status typing comes from @gathertown/webhook-object-types. now-playing-inbox no longer sends counter.increment after each new track.

Tooling: root Playwright / @vitest/browser* devDependencies and the CI Playwright Chromium install step are removed. pnpm-workspace.yaml allow-lists the two Gather SDK packages under minimumReleaseAgeExclude. Demo READMEs point at the npm SDK.

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[linear]

GCO-2137 Remove custom client

Swap this for our 1P client - https://github.com/gathertown/webhook-objects/tree/main/packages/client

Review in Linear

[gesposito]

• refactor: replace the custom client with @gathertown/webhook-object-sdk #15 👈 (View in Graphite)
• main

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[cursor]

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