docs: document daemon process management commands

Update README.md and CLAUDE.md to document new process management:
- Add "Process Management" section with daemon commands
- Update all examples to use `./kvs start/stop/status` instead of `&` and `pkill`
- Document global PID/log directories (~/.kvs/)
- Update cluster setup examples
- Update development workflow
- Add daemon package to project structure

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

README.md

@@ -69,11 +69,67 @@ go build -o kvs .
 
 ### Quick Test
 ```bash
-# Start standalone node
-./kvs
+# Start standalone node (uses config.yaml if it exists, or creates it)
+./kvs start config.yaml
 
 # Test the API
 curl http://localhost:8080/health
+
+# Check status
+./kvs status
+
+# Stop when done
+./kvs stop config
+```
+
+## 🎮 Process Management
+
+KVS includes systemd-style daemon commands for easy process management:
+
+```bash
+# Start as background daemon
+./kvs start config.yaml      # or just: ./kvs start config
+./kvs start node1.yaml       # Start with custom config
+
+# Check status
+./kvs status                 # Show all running instances
+./kvs status node1           # Show specific instance
+
+# Stop daemon
+./kvs stop node1             # Graceful shutdown
+
+# Restart daemon
+./kvs restart node1          # Stop and start
+
+# Run in foreground (traditional)
+./kvs node1.yaml             # Logs to stdout
+```
+
+### Daemon Features
+- **Global PID tracking**: PID files stored in `~/.kvs/pids/` (works from any directory)
+- **Automatic logging**: Logs written to `~/.kvs/logs/{config-name}.log`
+- **Flexible naming**: Config extension optional (`node1` or `node1.yaml` both work)
+- **Graceful shutdown**: SIGTERM sent for clean shutdown
+- **Stale PID cleanup**: Automatically detects and cleans dead processes
+- **Multi-instance**: Run multiple KVS instances on same machine
+
+### Example Workflow
+```bash
+# Start 3-node cluster as daemons
+./kvs start node1.yaml
+./kvs start node2.yaml
+./kvs start node3.yaml
+
+# Check cluster status
+./kvs status
+
+# View logs
+tail -f ~/.kvs/logs/kvs_node1.yaml.log
+
+# Stop entire cluster
+./kvs stop node1
+./kvs stop node2
+./kvs stop node3
 ```
 
 ## ⚙️ Configuration
@@ -308,17 +364,23 @@ clustering_enabled: true
 
 #### Start the Cluster
 ```bash
-# Terminal 1
-./kvs node1.yaml
-
-# Terminal 2 (wait a few seconds)
-./kvs node2.yaml
-
-# Terminal 3 (wait a few seconds)
-./kvs node3.yaml
+# Start as daemons
+./kvs start node1.yaml
+sleep 2
+./kvs start node2.yaml
+sleep 2
+./kvs start node3.yaml
 
 # Verify cluster formation
 curl http://localhost:8081/members/  # Should show all 3 nodes
+
+# Check daemon status
+./kvs status
+
+# Stop cluster when done
+./kvs stop node1
+./kvs stop node2
+./kvs stop node3
 ```
 
 ## 🔄 How It Works
@@ -364,9 +426,10 @@ go build -o kvs .
 ./integration_test.sh
 
 # Manual basic functionality test
-./kvs &
+./kvs start config.yaml
+sleep 2
 curl http://localhost:8080/health
-pkill kvs
+./kvs stop config
 
 # Manual cluster test (requires creating configs)
 echo 'node_id: "test1"
@@ -379,8 +442,9 @@ port: 8082
 seed_nodes: ["127.0.0.1:8081"]
 auth_enabled: false' > test2.yaml
 
-./kvs test1.yaml &
-./kvs test2.yaml &
+./kvs start test1.yaml
+sleep 2
+./kvs start test2.yaml
 
 # Test data replication (wait for cluster formation)
 sleep 10
@@ -393,7 +457,8 @@ sleep 30
 curl http://localhost:8082/kv/test/data
 
 # Cleanup
-pkill kvs
+./kvs stop test1
+./kvs stop test2
 rm test1.yaml test2.yaml
 ```
 
@@ -418,17 +483,22 @@ auth_enabled: false
 log_level: "debug"' > conflict2.yaml
 
 # Start nodes with conflicting data
-./kvs conflict1.yaml &
-./kvs conflict2.yaml &
+./kvs start conflict1.yaml
+sleep 2
+./kvs start conflict2.yaml
 
 # Watch logs for conflict resolution
+tail -f ~/.kvs/logs/kvs_conflict1.yaml.log ~/.kvs/logs/kvs_conflict2.yaml.log &
+
 # Both nodes will converge within ~10-30 seconds
 # Check final state
 sleep 30
 curl http://localhost:9111/kv/test/conflict/data
 curl http://localhost:9112/kv/test/conflict/data
 
-pkill kvs
+# Cleanup
+./kvs stop conflict1
+./kvs stop conflict2
 rm conflict1.yaml conflict2.yaml
 ```
 
@@ -474,6 +544,10 @@ kvs/
 ├── config/                    # Configuration management
 │   └── config.go             # Config loading & defaults
 │
+├── daemon/                    # Process management
+│   ├── daemonize.go          # Background process spawning
+│   └── pid.go                # PID file management
+│
 ├── features/                  # Utility features
 │   ├── auth.go               # Auth utilities
 │   ├── backup.go             # Backup system
@@ -580,8 +654,9 @@ type StoredValue struct {
 ## 🛡️ Production Considerations
 
 ### Deployment
-- Use systemd or similar for process management
-- Configure log rotation for JSON logs
+- Built-in daemon commands (`start`/`stop`/`restart`/`status`) for process management
+- Alternatively, use systemd or similar for advanced orchestration
+- Logs automatically written to `~/.kvs/logs/` (configure log rotation)
 - Set up monitoring for `/health` endpoint
 - Use reverse proxy (nginx/traefik) for TLS and load balancing