[FEATURE] Extend currentDate injection to include local time and timezone

Problem

Claude Code already injects \# currentDate\ (e.g. \Today's date is 2026-05-03\) into the system prompt — which is great. But it injects date only, with no time-of-day or timezone.

This leaves LLMs without the ability to:

• Accurately timestamp memory/knowledge-base entries mid-session
• Reason about time-sensitive operations (\"was this result from 10 minutes ago or 3 hours ago?\")
• Know what timezone the user is in

Current workaround: a \UserPromptSubmit\ hook that runs \date\ and injects the result into every prompt — functional but a hack that every user has to discover and implement independently.

Proposed Solution

Extend the existing \currentDate\ injection to include local time and timezone:

Today's date and time is 2026-05-03 17:29 CEST (UTC+2)

Or as structured data alongside the existing field:

Today's date is 2026-05-03
Current time is 17:29:45 CEST (UTC+2)

The timezone should reflect the user's local system timezone, not UTC.

Why This Is the Right Layer

This is an incremental improvement to an already-existing feature. CC already knows how to inject temporal context — it just stops at the date boundary. Time and timezone are equally available at the system level and equally useful to the model.

Related Issues

• https://github.com/anthropics/claude-code/issues/49084 — broader request for message-level timestamps
• https://github.com/anthropics/claude-code/issues/51110 — UTC vs local timezone bug in Routines
• https://github.com/anthropics/claude-code/issues/50499 — inconsistent date injection across clients