[Bug] Plan mode 'clear context' wipes entire conversation history, not just plan context

Environment

• Terminal: Warp
• Tool: Claude Code (CLI)
• OS: macOS Darwin 24.6.0

Steps to reproduce

1. Start a conversation in Claude Code via Warp terminal
2. Work on 2-3 features (without running /init before each)
3. Enter Plan Mode for a task
4. Claude proposes "yes, clear context"
5. Accept — entire conversation context is wiped, not just the plan mode context

Expected behavior

Previously, "clear context" in Plan Mode only cleared the plan mode session, preserving the conversation history above it. The full prior context (feature discussions, code changes, decisions) remained intact.

Actual behavior

Now "clear context" deletes everything — the entire conversation history is lost, including all prior feature work, decisions, and context from the session.

Additional context

• Cannot properly update CLAUDE.md via /init after context is cleared because all prior context is gone
• This is a regression — the previous behavior correctly scoped the context clearing to plan mode only
• Forces users to re-explain everything or start a fresh session

Impact

• Lost context means Claude loses awareness of all prior changes made in the session
• Breaks workflow when working on multiple features sequentially
• Significant productivity loss on complex multi-feature sessions