fix: support custom namespace prefix for electron IPC

[joker23]

This PR will implement support for running multiple LDClients with the same mobile key. We do this by adding an optional namespace option that will prefix IPC namespace to guard against any collisions when running 2 clients at once.

---

Note

Medium Risk
Changes how IPC channel names are derived for the Electron SDK and updates renderer/main wiring; misconfiguration or mismatched namespaces could break renderer↔main communication for existing multi-client setups.

Overview
Adds an optional namespace option to the Electron SDK to isolate IPC channel names so multiple clients can run in the same process even when sharing the same credential.

Main-process ElectronClient now derives an IPC namespace via new deriveNamespace() and registers all IPC handlers under that derived value; renderer-side ElectronRendererClient/createRendererClient accept the same optional namespace to connect to the matching channels.

Updates option validation and migration docs, and refactors/adds tests (including a new ElectronIPC.test.ts plus shared createMockLogger) to cover namespace derivation and the updated IPC wiring.

^{Reviewed by Cursor Bugbot for commit 793a40c. Bugbot is set up for automated code reviews on this repo. Configure here.}

---

[github-actions]

@launchdarkly/js-sdk-common size report
This is the brotli compressed size of the ESM build.
Compressed size: 25623 bytes
Compressed size limit: 29000
Uncompressed size: 125843 bytes

[github-actions]

@launchdarkly/js-client-sdk size report
This is the brotli compressed size of the ESM build.
Compressed size: 31681 bytes
Compressed size limit: 34000
Uncompressed size: 112864 bytes

[github-actions]

@launchdarkly/browser size report
This is the brotli compressed size of the ESM build.
Compressed size: 179425 bytes
Compressed size limit: 200000
Uncompressed size: 830054 bytes

[github-actions]

@launchdarkly/js-client-sdk-common size report
This is the brotli compressed size of the ESM build.
Compressed size: 37184 bytes
Compressed size limit: 38000
Uncompressed size: 204411 bytes

[joker23]

@cursor review

[joker23]

@cursor review

[joker23]

@cursor review

[joker23]

@cursor review

[joker23]

@cursor review

[joker23]

@cursor review

[cursor]

✅ Bugbot reviewed your changes and found no new issues!

Comment @cursor review or bugbot run to trigger another review on this PR

^{Reviewed by Cursor Bugbot for commit 3459aff. Configure here.}

[joker23]

@cursor review

[cursor]

✅ Bugbot reviewed your changes and found no new issues!

Comment @cursor review or bugbot run to trigger another review on this PR

^{Reviewed by Cursor Bugbot for commit c211d00. Configure here.}

[devin-ai-integration]

✅ Devin Review: No Issues Found

Devin Review analyzed this PR and found no potential bugs to report.

View in Devin Review to see 5 additional findings.

[joker23]

This is the wrong implementation