feat(kernel): persist agent runtime state across restarts

- Schema: migrations now execute ALTER TABLE ADD COLUMN for state/message_count
- MemoryStore: add update_agent_runtime() and list_agents_with_runtime()
- Registry: add register_with_runtime() to accept persisted state/message_count
- Kernel boot: restore agents with their persisted state (not always Running)
- Kernel shutdown: persist all agent states/message_counts before terminating

Agents that were suspended stay suspended after restart. Message counts
survive restarts instead of resetting to 0.

crates/zclaw-kernel/src/kernel/agents.rs

@@ -1,6 +1,6 @@
 //! Agent CRUD operations
 
-use zclaw_types::{AgentConfig, AgentId, AgentInfo, Event, Result};
+use zclaw_types::{AgentConfig, AgentId, AgentInfo, AgentState, Event, Result};
 
 #[cfg(feature = "multi-agent")]
 use std::sync::Arc;

crates/zclaw-kernel/src/kernel/mod.rs

@@ -12,7 +12,7 @@ mod a2a;
 
 use std::sync::Arc;
 use tokio::sync::{broadcast, Mutex};
-use zclaw_types::{Event, Result};
+use zclaw_types::{Event, Result, AgentState};
 
 #[cfg(feature = "multi-agent")]
 use zclaw_types::AgentId;
@@ -114,10 +114,21 @@ impl Kernel {
         // Initialize Growth system — shared VikingAdapter for memory storage
         let viking = Arc::new(zclaw_runtime::VikingAdapter::in_memory());
 
-        // Restore persisted agents
-        let persisted = memory.list_agents().await?;
-        for agent in persisted {
-            registry.register(agent);
+        // Restore persisted agents with their runtime state
+        let persisted = memory.list_agents_with_runtime().await?;
+        for (agent, state_str, msg_count) in persisted {
+            let state = match state_str.as_str() {
+                "running" => AgentState::Running,
+                "suspended" => AgentState::Suspended,
+                _ => AgentState::Terminated,
+            };
+            // Only auto-resume agents that were running; suspended/terminated stay as-is
+            let restored_state = if state == AgentState::Running {
+                AgentState::Running
+            } else {
+                state
+            };
+            registry.register_with_runtime(agent, restored_state, msg_count);
         }
 
         // Initialize A2A router for multi-agent support
@@ -287,6 +298,23 @@ impl Kernel {
 
     /// Shutdown the kernel
     pub async fn shutdown(&self) -> Result<()> {
+        // Persist all agent runtime states before shutdown
+        let agents = self.registry.list();
+        for info in &agents {
+            let state_str = match info.state {
+                AgentState::Running => "running",
+                AgentState::Suspended => "suspended",
+                AgentState::Terminated => "terminated",
+            };
+            if let Err(e) = self.memory
+                .update_agent_runtime(&info.id, state_str, info.message_count as u64)
+                .await
+            {
+                tracing::warn!("[Kernel] Failed to persist agent {} state: {}", info.id, e);
+            }
+        }
+        tracing::info!("[Kernel] Persisted runtime state for {} agents", agents.len());
+
         self.events.publish(Event::KernelShutdown);
         Ok(())
     }