docs(02-02): complete tool framework and audit logging plan

- 02-02-SUMMARY.md: tool registry, executor, 4 built-in tools, immutable audit trail
- STATE.md: progress 89%, decisions recorded, session updated
- ROADMAP.md: phase 2 plan progress updated (4 of 5 summaries)
- REQUIREMENTS.md: AGNT-04 and AGNT-06 marked complete

.planning/REQUIREMENTS.md

@@ -20,9 +20,9 @@ Requirements for beta-ready release. Each maps to roadmap phases.
 - [x] **AGNT-01**: Tenant can configure a single AI employee with custom name, role, and persona
 - [x] **AGNT-02**: Agent maintains conversational memory within sessions (sliding window)
 - [x] **AGNT-03**: Agent retrieves relevant past context via vector search (pgvector long-term memory)
-- [ ] **AGNT-04**: Agent can invoke registered tools to perform actions (tool registry + execution)
+- [x] **AGNT-04**: Agent can invoke registered tools to perform actions (tool registry + execution)
 - [x] **AGNT-05**: Agent escalates to human when configured rules trigger, transferring full conversation context
-- [ ] **AGNT-06**: Every agent action (LLM call, tool invocation, handoff) is logged in an audit trail
+- [x] **AGNT-06**: Every agent action (LLM call, tool invocation, handoff) is logged in an audit trail
 - [ ] **AGNT-07**: Agent token usage is tracked per-agent per-tenant with configurable budget limits
 
 ### LLM Backend
@@ -103,9 +103,9 @@ Which phases cover which requirements. Updated during roadmap creation.
 | AGNT-01 | Phase 1 | Complete |
 | AGNT-02 | Phase 2 | Complete |
 | AGNT-03 | Phase 2 | Complete |
-| AGNT-04 | Phase 2 | Pending |
+| AGNT-04 | Phase 2 | Complete |
 | AGNT-05 | Phase 2 | Complete |
-| AGNT-06 | Phase 2 | Pending |
+| AGNT-06 | Phase 2 | Complete |
 | AGNT-07 | Phase 3 | Pending |
 | LLM-01 | Phase 1 | Complete |
 | LLM-02 | Phase 1 | Complete |