[Refactor]: Agent System Refactor / [Refactor]: Agent系统重构

Purpose

As PicoClaw evolves, we're seeing growing complexity in the agent layer (pkg/agent/loop.go, now ~1200 LOC).

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Current Pain Points

1. Monolithic structure - loop.go mixes routing, LLM iteration, tool execution, context management, summarization
2. Reactive context handling - Emergency compression when we hit limits, losing user context abruptly
3. Tool coupling - Tools have implicit dependencies on agent loop internals
4. Limited observability - Hard to debug execution flow across tool calls and LLM interactions
5. Session consistency risks - No explicit serialization, potential race conditions in multi-channel scenarios
6. Write-only memory - MEMORY.md exists but agent can't search/retrieve past information
7. Flat tool permissions - No per-agent or per-channel tool restrictions

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Related Issues & PRs

Roadmap

• #296
• #295
• #294
• #290
• #284

Issue

• #773

PR