fix: 4 pre-release bug fixes — identity override, model config, agent sync, auto-identity

P1: identity.rs get_identity() returns empty soul/instructions for agents
without explicit identity files. This prevents the default ZCLAW personality
from overriding agent_config.system_prompt. New get_identity_or_default()
method added for the DEFAULT agent.

P2: messaging.rs now uses agent_config.model.model when available, falling
back to global Kernel config. This allows per-agent model selection.

P2: agentStore.ts loadClones retries up to 3 times (300ms interval) when
getClient() returns null, handling the coordinator initialization race.

P2: agent_create Tauri command auto-populates identity files (soul +
instructions) from creation parameters, ensuring build_system_prompt()
has content for new agents.

Also fixes conversationStore upsertActiveConversation to persist generated
conversation IDs, preventing duplicate entries on new conversations.

desktop/src-tauri/src/kernel_commands/agent.rs

@@ -7,6 +7,7 @@ use zclaw_types::{AgentConfig, AgentId, AgentInfo};
 
 use super::{validate_agent_id, KernelState};
 use crate::intelligence::validation::validate_string_length;
+use crate::intelligence::identity::IdentityManagerState;
 
 // ---------------------------------------------------------------------------
 // Request / Response types
@@ -71,6 +72,7 @@ pub struct AgentUpdateRequest {
 #[tauri::command]
 pub async fn agent_create(
     state: State<'_, KernelState>,
+    identity_state: State<'_, IdentityManagerState>,
     request: CreateAgentRequest,
 ) -> Result<CreateAgentResponse, String> {
     // Input validation
@@ -90,6 +92,10 @@ pub async fn agent_create(
     let kernel = kernel_lock.as_ref()
         .ok_or_else(|| "Kernel not initialized. Call kernel_init first.".to_string())?;
 
+    // Capture identity-relevant fields before moving request
+    let soul_content = request.soul.clone();
+    let system_prompt_content = request.system_prompt.clone();
+
     let mut config = AgentConfig::new(&request.name)
         .with_description(request.description.unwrap_or_default())
         .with_system_prompt(request.system_prompt.unwrap_or_default())
@@ -114,8 +120,30 @@ pub async fn agent_create(
         .await
         .map_err(|e| format!("Failed to create agent: {}", e))?;
 
+    let agent_id_str = id.to_string();
+
+    // Auto-populate identity files from creation parameters.
+    // This ensures the identity system has content for `build_system_prompt()`.
+    {
+        let mut identity_mgr = identity_state.lock().await;
+        if let Some(soul) = soul_content {
+            if !soul.is_empty() {
+                if let Err(e) = identity_mgr.update_file(&agent_id_str, "soul", &soul) {
+                    tracing::warn!("[agent_create] Failed to write soul to identity: {}", e);
+                }
+            }
+        }
+        if let Some(prompt) = system_prompt_content {
+            if !prompt.is_empty() {
+                if let Err(e) = identity_mgr.update_file(&agent_id_str, "instructions", &prompt) {
+                    tracing::warn!("[agent_create] Failed to write instructions to identity: {}", e);
+                }
+            }
+        }
+    }
+
     Ok(CreateAgentResponse {
-        id: id.to_string(),
+        id: agent_id_str,
         name: request.name,
         state: "running".to_string(),
     })