feat: show timestamp and duration on tool execution blocks

[kshptl]

Issue for this PR

Closes #22144

Type of change

• Bug fix
• New feature
• Refactor / code improvement
• Documentation

What does this PR do?

Shows a clock timestamp and running duration on every tool execution block in both the web UI and TUI. While a tool is running, the timer ticks live every second. Once completed, it freezes at the final duration.

Interrupted/aborted tools display "Interrupted" in red instead of a misleading "0s" duration.

Web UI: New shared utility module (tool-timing.ts) with locale-aware formatting via Intl.DateTimeFormat/Intl.NumberFormat. Reactive SolidJS hooks track timing state per tool part. Timing appears on all tool types — reads, edits, grep, bash, tasks, etc.

TUI: Extracted createTiming hook used by both BlockTool and InlineTool (including spinner branch for running tools). Local formatting helpers use system locale.

Backend fix: prompt.ts now preserves the existing start timestamp when a tool's metadata callback fires during execution, preventing the timer from resetting mid-run. Task-tool cancellation sets metadata.interrupted: true.

How did you verify your code works?

• bun typecheck clean across all 13 packages (runs via pre-push hook)
• 13 unit tests passing in packages/ui covering duration formatting, header timing, zero-duration edge cases, and interrupt detection
• Reviewed tool state machine in processor.ts — timing survives all transitions (pending → running → completed/error)

Screenshots / recordings

Screenshots of the running timer and interrupted state to be added.

Checklist

• I have tested my changes locally
• I have not included unrelated changes in this PR

[github-actions]

The following comment was made by an LLM, it may be inaccurate:

Potential Related PR Found:

• PR feat(tui): live per-message response timing #20220 - feat(tui): live per-message response timing
  • feat(tui): live per-message response timing #20220
  • Why it's related: This PR also implements live timing display in the TUI. While PR feat: show timestamp and duration on tool execution blocks #22145 focuses specifically on tool execution block timing with interruption handling, PR feat(tui): live per-message response timing #20220 addresses per-message response timing. There may be overlapping work on timing infrastructure, display logic, or formatting utilities that could affect both features.

Note: PR #22145 is the current PR, so it's excluded from the duplicate list.