[FEATURE]: Show timestamp on permission prompts (Ask/Approve dialogs)

Feature Request: Show timestamp on permission prompts

Description

When OpenCode prompts for approval (e.g., "Do you want to allow this bash command?"), include the current date/time so the user has temporal context for the request.

Use case

Permission prompts currently show the tool name and arguments, but not when the request was made. For long-running sessions where many minutes pass between user prompts (and the agent is thinking, then proposing), the user has no easy way to know how stale a prompt is.

Example scenario:

• Agent says "Voy a hacer X" at 10:00
• Agent enters thinking mode for 8 minutes
• Permission prompt appears at 10:08 with the proposed action
• User has no easy way to see how long the agent took between planning and executing

Proposed display

Add a small timestamp to the permission prompt, similar to how /thinking and timestamps on messages already work:

┌─────────────────────────────────────────────┐
│ Permission Required                         │
│ Shell command                               │
│                                              │
│ $ git push origin develop                   │
│                                              │
│ Asked: 08/08/2026 14:32:11                   │ ← new field
│                                              │
│ [once]  [always]  [reject]                  │
└─────────────────────────────────────────────┘

The exact format can match the existing timestamps config in kv.json ("show" | "hide"), so users who already disabled timestamps get consistent behavior.

Why this is useful

1. Audit trail — knowing when a permission was asked helps with reviewing past decisions
2. Staleness check — if a prompt has been waiting too long, user knows the context may have changed
3. Debugging loops — helps identify when the agent is stuck in long-thinking cycles
4. Consistency with existing timestamps — kv.json: "timestamps": "show" already works for chat messages; this would extend that to permission prompts

Related existing functionality

• kv.json: timestamps: show — toggles timestamps on chat messages (already works)
• tui.json: keybinds.session_toggle_timestamps — keybind for the toggle
• tui.json: keybinds.session_timeline — keybind for session timeline

Acceptance criteria

• Permission prompts show current timestamp by default (when kv.json: timestamps: "show")
• When kv.json: timestamps: "hide", permission prompt does NOT show timestamp (consistent with chat messages)
• Timestamp format is consistent with existing chat message timestamps
• Works across all permission prompt types: bash, edit, webfetch, question, etc.

Environment

• OpenCode version: 1.18.10
• TUI mode (gnome-terminal on Wayland)
• kv.json: timestamps: show

Workaround (current)

For now, the user has to either:

• Track time manually while watching the agent
• Use external watch -n 1 date in another terminal
• Wait for the chat message timestamp (already visible) to estimate

None of these are integrated with the actual permission prompt.