WebSocket client: envelope protocol, resume + sync

[codebestia]

Description:
Update the web socket client to: authenticate with the device-bound token (#108), speak the event envelope (#143), send per-device send_message (#181), handle delivery/read receipts, typing, presence, resume (#150) on reconnect, then run /sync (#137) to backfill missed envelopes. Optimistic UI with reconciliation on ACK (sequenceNumber).

Acceptance criteria:

• Reconnect triggers resume + sync, no missed/dup messages
• Optimistic send reconciled with server sequenceNumber
• Receipts/typing/presence reflected in UI

[OG-wura]

@OG-wura has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hello maintainer. I would love to work on this. I can fix it

ℹ️ Repo Maintainers: To accept this application, review their application or assign @OG-wura to this issue.

[deep-bhikadiya]

@deep-bhikadiya has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hello, this looks like something I can help with. I’ll work on the PR today and share it once it’s ready.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @deep-bhikadiya to this issue.

[veloura-dev]

@veloura-dev has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

please maintainer ,ill love to work on this issue , expect PR ASAP WITHOUT ERRORS

ℹ️ Repo Maintainers: To accept this application, review their application or assign @veloura-dev to this issue.

[drips-wave]

Congratulations, @veloura-dev! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 30, 2026.

🧑‍💻 @veloura-dev: Please resolve the issue such that the repo's maintainers have enough time to review your contribution before the due date. You'll earn Points for completing the issue on-time, which will make you eligible for a share of the Stellar Wave Program's reward pool.

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