Bug: Control UI (webchat) creates new session on every WebSocket reconnection

Environment:

• OpenClaw: v2026.4.15
• OS: Windows 10
• Channel: webchat (Control UI)
• Model: MiniMax-M2.7

Description:
When using the Control UI (webchat), a new session is created on every WebSocket disconnection/reconnection instead of resuming the previous session. This causes context loss and a poor user experience.

Expected behavior:
When the webchat WebSocket reconnects (after network hiccup, browser tab minimize/restore, or page refresh), the existing session should be resumed, not replaced with a new one.

Actual behavior:

1. User is in an active session
2. WebSocket disconnects (even briefly)
3. Gateway creates a brand new session on reconnection
4. Previous session context is lost from the user's perspective

Session timeline observed today (2026-04-17):

22:07  d6b5f8ec (3MB session) ← compacted
22:17  81b0ede9 (34KB)
22:12  49fff9a4 (1MB) ← user said "why did it refresh again"
22:24-26  49fff9a4 checkpoint files created (4 compactions)
22:26  49fff9a4 last activity
22:34  0ed63899 (current) ← new session created due to reconnect

Investigation findings:

• parentForkMaxTokens: 0 is correctly set (no auto-fork on compaction threshold)
• Compaction works correctly and creates checkpoint files
• The Gateway process stays stable — sessions are preserved server-side
• The issue is specifically: webchat frontend reconnects → Gateway creates new session instead of resuming
• This appears to be a webchat session recovery logic bug in the EC() function on the frontend

Workaround:
Keep the Control UI tab open without refreshing/minimizing. But this is not practical for normal use.