Subagents don't inherit session-level permissions

Bug

When I select **"Yes, and don't ask again for: git add:\"* in the permission prompt, the preference is not inherited by subagents spawned in the same session. Each subagent re-prompts for the same permission.

Expected behavior

Permission inheritance should follow this chain:

1. Session start/resume: read global permissions → merge project permissions (allow/deny) → merge session permissions (allow/deny)
2. Subagent start: same chain — global → project → session
3. "Don't ask again" writes: persist to session level. May optionally also store at project or global level if appropriate.

This means a permission granted once in a session should apply to all subagents within that session without re-prompting.

Actual behavior

• User selects option 2 ("Yes, and don't ask again for: git add:\*")
• The rule appears in .claude/settings.local.json under permissions.allow
• A subagent dispatched via the Agent tool prompts again for the same git add command
• This happens repeatedly — every subagent re-prompts

Reproduction

1. Start a Claude Code session
2. Run a command that triggers a permission prompt (e.g., git add)
3. Select "Yes, and don't ask again"
4. Dispatch a subagent (via Agent tool) that runs the same command
5. Observe: the subagent prompts again for the same permission

Impact

For workflows that dispatch multiple subagents (e.g., subagent-driven development with implementer + reviewer agents), the user gets prompted 2-3x per task for permissions they've already permanently approved. This is especially disruptive when the user is AFK and has given explicit permission to proceed autonomously.

Environment

• Claude Code (CLI)
• macOS