fix: lint issues, add GetAgent to Runtime, wire verifyRestoredState in example

  - Fix 32 errcheck/ineffassign/SA1012/unused lint issues across 7 test files
  - Add GetAgent(agentID) method to runtime.Manager for agent lookup
  - Wire verifyRestoredState() call in runtime_resurrection example
  - Remove ineffectual assignment in pg_store_test.go
  - Add nolint directive for intentional nil context test

Author: Timwood0x10

docs/README.md

@@ -2,7 +2,13 @@
 
 Welcome to the GoAgent framework documentation center.
 
-## Documentation Languages
+## Release Notes / 发布说明
+
+| Version | 中文 | English |
+|---------|------|---------|
+| v0.2.0 | [发布说明](./zh/releases/v0.2.0.md) | [Release Notes](./en/releases/v0.2.0.md) |
+
+## Documentation Languages / 文档语言
 
 - **[中文文档](./zh/)** — Chinese documentation
 - **[English Docs](./en/)** — English documentation

docs/en/releases/v0.2.0.md

@@ -0,0 +1,291 @@
+# GoAgent v0.2.0 Release Notes
+
+**Release Date:** 2026-06-12
+**Branch:** improve
+**Commits:** 119 files changed, 22,634 insertions, 1,302 deletions
+
+---
+
+## Overview
+
+v0.2.0 introduces a Runtime layer for agent lifecycle management, event sourcing for operational recovery, a dynamic workflow engine with human-in-the-loop support, and a pluggable vector store interface. The focus shifts from "agents manage themselves" to "Runtime manages agents" — agents become disposable executors.
+
+---
+
+## Architecture Changes
+
+### Before (v0.1.x)
+
+```
+Leader Agent
+├── manages sub-agents
+├── manages own lifecycle
+├── manages own memory
+└── single point of failure
+```
+
+### After (v0.2.0)
+
+```
+Runtime Layer
+├── manages ALL agent lifecycles
+├── resurrects failed agents
+├── replays events for state recovery
+│
+├── EventStore (operational recovery)
+│   └── "What step was I on?"
+│
+├── MemoryStore (cognitive recovery)
+│   └── "Who am I? Why did I do this?"
+│
+└── Agents (disposable executors)
+    ├── Leader Agent
+    ├── Sub Agents
+    └── Custom Agents
+```
+
+Key principle: **Agents are disposable executors. Real state lives in EventStore and MemoryStore.**
+
+---
+
+## New Features
+
+### 1. Runtime Layer (`internal/runtime/`)
+
+Agent lifecycle management with automatic resurrection.
+
+```go
+type Runtime interface {
+    StartAgent(ctx, agent) error
+    StopAgent(ctx, agentID) error
+    RestartAgent(ctx, agentID) error
+    RestoreAgent(ctx, agentID, factory) error
+    NotifyAgentDead(agentID, reason)
+    RegisterAgent(agent, factory)
+    Start(ctx) error
+    Stop() error
+    Stats() RuntimeStats
+}
+```
+
+- `NotifyAgentDead` — non-blocking, triggers async resurrection
+- `RestoreAgent` — factory → replayEvents → RestoreState → Start
+- Concurrent shutdown with configurable timeout
+- Panic recovery in all agent goroutines
+
+### 2. Event Sourcing (`internal/events/`)
+
+EventStore interface with two implementations.
+
+```go
+type EventStore interface {
+    Append(ctx, streamID, events, expectedVersion) error
+    Read(ctx, streamID, opts) ([]*Event, error)
+    ReadAll(ctx, opts) ([]*Event, error)
+    Subscribe(ctx, filter) (<-chan *Event, error)
+    StreamVersion(ctx, streamID) (int64, error)
+}
+```
+
+- **MemoryEventStore** — in-memory, for dev/test
+- **PostgresEventStore** — PostgreSQL with optimistic concurrency
+- 17 event types covering agent lifecycle, tasks, memory, workflow
+- DLQ auto-retry with MaxRetries
+
+### 3. Dynamic Workflow Engine (`internal/workflow/engine/`)
+
+Runtime-mutable DAG with HITL support.
+
+- **MutableDAG** — AddNode/RemoveNode/AddEdge/RemoveEdge with incremental BFS cycle detection
+- **DynamicExecutor** — ApplyAtCheckpoint / ApplyImmediate modes
+- **GraphEventHub** — pub/sub for mutation notifications
+- **HITL** — InterruptConfig on steps, InterruptHandler, InterruptStore
+
+### 4. Pluggable Vector Store (`internal/storage/`)
+
+```go
+type VectorStore interface {
+    Search(ctx, table, embedding, limit) ([]*SearchResult, error)
+    AddEmbedding(ctx, table, id, embedding, metadata) error
+    CreateCollection(ctx, name, dimension) error
+}
+```
+
+- **PostgreSQL + pgvector** — production implementation
+- **In-memory** — dev/test implementation
+- Users can plug in Qdrant, Milvus, SQLite, Elasticsearch, or custom backends
+
+### 5. StatefulAgent Interface (`internal/agents/base/`)
+
+```go
+type StatefulAgent interface {
+    RestoreState(state map[string]any) error
+    ReplayEvents(events []*Event) error
+    Snapshot() (map[string]any, error)
+}
+```
+
+Both leader and sub agents implement this interface with compile-time checks.
+
+### 6. Resurrection Plugin (`internal/plugins/resurrection/`)
+
+Pluggable agent resurrection via HealthChecker interface.
+
+- `HeartbeatAdapter` bridges AHP heartbeat to HealthChecker
+- `Supervisor` with concurrent resurrection deduplication
+- Factory-based recovery — each agent type provides its own factory
+
+### 7. WorkflowService API (`api/core/workflow.go`, `api/service/workflow/`)
+
+High-level workflow orchestration abstraction.
+
+```go
+type WorkflowService interface {
+    Execute(ctx, req) (*WorkflowResponse, error)
+    ExecuteStream(ctx, req) (<-chan WorkflowEvent, error)
+    ListWorkflows(ctx) ([]*WorkflowSummary, error)
+    GetWorkflow(ctx, id) (*WorkflowDefinition, error)
+}
+```
+
+---
+
+## Bug Fixes (50 total)
+
+### Storage (12)
+- Embedding queue dedup key mismatch (SHA256 vs MD5)
+- Write buffer data loss on Stop()
+- Transactional EnqueueTx for atomic writes
+- FOR UPDATE SKIP LOCKED without transaction
+- Reconcile threshold time arithmetic (Go duration vs PG interval)
+- ManagedRow connection leak (missing finalizer)
+- Missing migration tables (4 tables)
+- Circuit breaker halfOpen cleanup
+- safeFormatTable returning empty string
+- Immediate retry on flush failure
+- VectorSearcher dimension validation
+- Enqueue silent on duplicate (now returns ErrDuplicateTask)
+
+### Workflow (8)
+- Panic recovery ordering (wg.Done after recover)
+- Graph executor in-degree tracking
+- Deadlock false positive (stepDone channel)
+- DynamicExecutor hang on node removal (synthetic skipped result)
+- stepEg.Wait() concurrent with Go()
+- Duplicate step ID detection
+- MaxAttempts=0 clamp
+- recomputeOrder version-check race
+
+### AHP Protocol (7)
+- Send on closed channel (recover guard)
+- HeartbeatSender Start/Stop race
+- getRandomSuffix nil dereference
+- SendMessage error preservation
+- Protocol.Close() method
+- Peek() atomicity
+- DLQ.Remove trailing pointer
+
+### Agent System (8)
+- WaitGroup panic in finalizeMemory
+- Start/Stop TOCTOU race
+- Process mutual exclusion
+- Start partial validation cleanup
+- subAgent ProcessStream goroutine leak
+- doFailover cancelled context
+- Dispatcher partial results
+- streamEg tied to stopCh
+
+### Runtime (5)
+- Nil errgroup panic before Start()
+- Stop() data race on ma.stopped
+- Unbounded event replay (MaxReplayEvents=10000)
+- buildCognitiveState DB call timeout
+- Stop() using cancelled context
+
+### Event Sourcing (5)
+- FromVersion inclusive/exclusive semantics
+- Since filter inclusive semantics
+- ReadAll ignoring FromVersion
+- PostgreSQL unique violation → ErrVersionConflict
+- ConcurrentAppend test verification
+
+### Other (5)
+- SA5011 nil-pointer in 17 test files
+- SA1012 nil context in test
+- errcheck in integration tests
+- Mermaid diagram errors in README
+- safeFormatTable return value
+
+---
+
+## Infrastructure
+
+- **CI/CD**: GitHub Actions pipeline (lint, test, integration, benchmark)
+- **Integration Tests**: 60+ tests across 12 test files
+- **Benchmarks**: 36 benchmarks with count=3, updated report
+- **Documentation**: Bilingual (en/zh), 12 new docs
+- **Examples**: 6 runnable examples in `examples/advanced/`
+
+---
+
+## Breaking Changes
+
+| Change | Before | After |
+|--------|--------|-------|
+| `NewLeaderSupervisor` signature | 4 params | 5 params (added `eventStore`) |
+| `NewColdRestartStrategy` signature | 2 params | 3 params (added `checkpoint`) |
+| `MemoryManager` interface | 11 methods | 12 methods (added `GetLatestSessionForLeader`) |
+| `Repository.Vector` field | `*VectorSearcher` | `storage.VectorStore` |
+| `StatefulAgent` interface | `RestoreState` only | + `ReplayEvents`, `Snapshot` |
+
+---
+
+## Benchmark Results
+
+Platform: Apple M3 Max, Go 1.26.4, darwin/arm64
+
+| Category | Benchmarks | Hot (< 1μs) | Normal (1-100μs) | Cold (> 100μs) |
+|----------|-----------|-------------|-------------------|-----------------|
+| Eval | 5 | 2 | 2 | 1 |
+| Handler | 3 | 1 | 2 | 0 |
+| Tools/Core | 9 | 6 | 3 | 0 |
+| Distillation | 9 | 4 | 4 | 1 |
+| Errors | 4 | 4 | 0 | 0 |
+| Event Sourcing | 6 | 4 | 1 | 1 |
+| **Total** | **36** | **21** | **12** | **3** |
+
+Selected hot-path results:
+
+| Operation | ns/op | allocs/op |
+|-----------|-------|-----------|
+| ResultCreation | 0.27 | 0 |
+| Wrap | 0.28 | 0 |
+| ExactMatchEvaluator | 3.11 | 0 |
+| ToolExecution | 14.66 | 0 |
+| ParameterValidation | 7.26 | 0 |
+| ConflictDetection | 1,067 | 0 |
+| MemoryStore_Append | 563 | 7 |
+| MemoryStore_ConcurrentAppend | 707 | 6 |
+
+---
+
+## Migration Guide
+
+### From v0.1.x to v0.2.0
+
+1. **Runtime is optional.** Existing code using `LeaderSupervisor` continues to work. Migrate to `Runtime` when ready.
+
+2. **EventStore is optional.** Existing checkpoint-based recovery continues to work. Add EventStore for richer recovery.
+
+3. **VectorStore is a drop-in replacement.** `Repository.Vector` is now an interface. Existing `*VectorSearcher` satisfies it automatically.
+
+4. **StatefulAgent is opt-in.** Only implement if you want your agents to support resurrection via event replay.
+
+---
+
+## What's Next (v0.3.0)
+
+- SQLite + sqlite-vec compatibility (VectorStore interface ready)
+- Distributed Runtime (multi-node agent management)
+- Enhanced HITL (approval workflows, multi-step review)
+- Performance optimization (TopNFilter regression investigation)