fix: debug nudge phantom turn loop

[ranxianglei]

Problem

When config.debug: true, ACP's debug notifications used sendIgnoredMessage() to persist nudge text and compress notifications to the conversation DB as ignored: true user messages. opencode's runtime loop detects the last user message by role == "user" WITHOUT checking the ignored flag, so the phantom user message triggers a new turn → model keeps working → calls compress → another notification → infinite loop.

Reported in issue #20 floor 1734.

Fix

Removed ALL sendIgnoredMessage calls from debug-mode notification paths:

1. lib/hooks.ts (debug nudge callback): Removed sendIgnoredMessage, kept logger.debug + showToast
2. lib/ui/notification.ts (debug compress notification): Replaced sendIgnoredMessage with logger.debug, kept showToast

Both sites now use logger.debug (file log) + showToast (popup) for debug visibility, without writing to the conversation DB.

Verification

• TypeScript: 0 errors
• Tests: 954 pass, 0 fail
• Build: 386.21 KB
• Deployed locally to ~/.cache/opencode/packages/opencode-acp@latest/