Context

PR #1059 implemented token-based personality trimming via PromptProfile.max_personality_tokens. During review, a personality_trimming_notify setting and WsEventType.PERSONALITY_TRIMMED enum were initially added but removed because no code consumed them -- they were dead scaffolding.

This issue tracks implementing the complete notification feature as a unit.

Scope

Setting

• Add personality_trimming_notify setting in the ENGINE namespace (boolean, default true, yaml_path="engine.personality_trimming_notify")
• Setting controls whether a WebSocket event is published when personality trimming activates

WebSocket event

• Add WsEventType.PERSONALITY_TRIMMED = "personality.trimmed" enum member
• Decide which WS channel to publish on (likely system or a new engine channel)
• Add 'personality.trimmed' to frontend WsEventType in web/src/api/types.ts
• If new channel: add to WS_CHANNELS in frontend types and subscribe in the WebSocket store

Publisher

• In AgentEngine._prepare_context, after logging PROMPT_PERSONALITY_TRIMMED, read the personality_trimming_notify setting and publish a WsEvent when enabled
• Payload: agent_id, agent_name, task_id, before_tokens, after_tokens, max_tokens, trim_tier, budget_met

Frontend (optional, can be separate issue)

• Handle the event in the WebSocket store
• Display a toast or notification when personality trimming occurs

Tests

• Setting registration and defaults
• Publisher emits event when setting is true
• Publisher suppresses event when setting is false
• Frontend type sync

References

• Parent: feat: token-based personality trimming via PromptProfile.max_personality_tokens #1045 (token-based personality trimming)
• PR: feat: token-based personality trimming via PromptProfile.max_personality_tokens #1059 (implementation)