Show absolute timestamp (like WhatsApp) instead of relative "X minutes ago"

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

With showMessageTimestamps: true set in settings.json, Claude Desktop renders each assistant message's timestamp as a relative string ("há 24 minutos" / "24 minutes ago"). For messages more than a few minutes old this becomes imprecise and requires mental math to know exactly when a response arrived — especially when reviewing a long-running or async session later. I also tried hovering over the relative label to see if a tooltip with the exact time would appear (a common pattern in chat apps), and it does not — hovering shows nothing beyond the relative text.

Proposed Solution

Render an absolute timestamp instead, similar to how WhatsApp and most chat apps show it:

• Same-day messages: HH:MM (e.g. 13:35)
• Older messages: DD/MM, HH:MM (e.g. 27/07, 13:35)

Alternative Solutions

If switching to absolute-only by default isn't desired, an acceptable alternative would be a hover tooltip on the existing relative label showing the exact date/time. Currently there is no such tooltip — I checked.

Priority

Critical - Blocking my work

Feature Category

CLI commands and flags

Use Case Example

_No response_

Additional Context

_No response_