fix: make time optional in session update endpoint

[simon-leetmaa]

Summary

The time field in the PATCH /session/:sessionID endpoint was required, but callers like DialogSessionRename only send title when renaming a session. This caused validation failures.

Changes

• Made time optional in the session update request body schema
• Regenerated SDK to reflect the change

Why this fix

This is a PATCH endpoint for partial updates - both title and time.archived are independent optional fields. The handler already used optional chaining (updates.time?.archived) expecting time to be undefined.

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This PR was written with AI assistance (Claude Opus 4.5 via OpenCode).