fix(desktop): DeerFlow UI — ChatArea refactor + ai-elements + dead CSS cleanup

ChatArea retry button uses setInput instead of direct sendToGateway,
fix bootstrap spinner stuck for non-logged-in users,
remove dead CSS (aurora-title/sidebar-open/quick-action-chips),
add ai components (ReasoningBlock/StreamingText/ChatMode/ModelSelector/TaskProgress),
add ClassroomPlayer + ResizableChatLayout + artifact panel

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

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

@@ -249,3 +249,130 @@ pub async fn kernel_shutdown(
 
     Ok(())
 }
+
+/// Apply SaaS-synced configuration to the Kernel config file.
+///
+/// Writes relevant config values (agent, llm categories) to the TOML config file.
+/// The changes take effect on the next Kernel restart.
+#[tauri::command]
+pub async fn kernel_apply_saas_config(
+    configs: Vec<SaasConfigItem>,
+) -> Result<u32, String> {
+    use std::io::Write;
+
+    let config_path = zclaw_kernel::config::KernelConfig::find_config_path()
+        .ok_or_else(|| "No config file path found".to_string())?;
+
+    // Read existing config or create empty
+    let existing = if config_path.exists() {
+        std::fs::read_to_string(&config_path).unwrap_or_default()
+    } else {
+        String::new()
+    };
+
+    let mut updated = existing;
+    let mut applied: u32 = 0;
+
+    for config in &configs {
+        // Only process kernel-relevant categories
+        if !matches!(config.category.as_str(), "agent" | "llm") {
+            continue;
+        }
+
+        // Write key=value to the [llm] or [agent] section
+        let section = &config.category;
+        let key = config.key.replace('.', "_");
+        let value = &config.value;
+
+        // Simple TOML patching: find or create section, update key
+        let section_header = format!("[{}]", section);
+        let line_to_set = format!("{} = {}", key, toml_quote_value(value));
+
+        if let Some(section_start) = updated.find(&section_header) {
+            // Section exists, find or add the key within it
+            let after_header = section_start + section_header.len();
+            let next_section = updated[after_header..].find("\n[")
+                .map(|i| after_header + i)
+                .unwrap_or(updated.len());
+
+            let section_content = &updated[after_header..next_section];
+            let key_prefix = format!("\n{} =", key);
+            let key_prefix_alt = format!("\n{}=", key);
+
+            if let Some(key_pos) = section_content.find(&key_prefix)
+                .or_else(|| section_content.find(&key_prefix_alt))
+            {
+                // Key exists, replace the line
+                let line_start = after_header + key_pos + 1; // skip \n
+                let line_end = updated[line_start..].find('\n')
+                    .map(|i| line_start + i)
+                    .unwrap_or(updated.len());
+                updated = format!(
+                    "{}{}{}\n{}",
+                    &updated[..line_start],
+                    line_to_set,
+                    if line_end < updated.len() { "" } else { "" },
+                    &updated[line_end..]
+                );
+                // Remove the extra newline if line_end included one
+                updated = updated.replace(&format!("{}\n\n", line_to_set), &format!("{}\n", line_to_set));
+            } else {
+                // Key doesn't exist, append to section
+                updated.insert_str(next_section, format!("\n{}", line_to_set).as_str());
+            }
+        } else {
+            // Section doesn't exist, append it
+            updated = format!("{}\n{}\n{}\n", updated.trim_end(), section_header, line_to_set);
+        }
+        applied += 1;
+    }
+
+    if applied > 0 {
+        // Ensure parent directory exists
+        if let Some(parent) = config_path.parent() {
+            std::fs::create_dir_all(parent).map_err(|e| format!("Failed to create config dir: {}", e))?;
+        }
+
+        let mut file = std::fs::File::create(&config_path)
+            .map_err(|e| format!("Failed to write config: {}", e))?;
+        file.write_all(updated.as_bytes())
+            .map_err(|e| format!("Failed to write config: {}", e))?;
+
+        tracing::info!(
+            "[kernel_apply_saas_config] Applied {} config items to {:?} (restart required)",
+            applied,
+            config_path
+        );
+    }
+
+    Ok(applied)
+}
+
+/// Single config item from SaaS sync
+#[derive(Debug, Clone, serde::Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct SaasConfigItem {
+    pub category: String,
+    pub key: String,
+    pub value: String,
+}
+
+/// Quote a value for TOML format
+fn toml_quote_value(value: &str) -> String {
+    // Try to parse as number or boolean
+    if value == "true" || value == "false" {
+        return value.to_string();
+    }
+    if let Ok(n) = value.parse::<i64>() {
+        return n.to_string();
+    }
+    if let Ok(n) = value.parse::<f64>() {
+        return n.to_string();
+    }
+    // Handle multi-line strings with TOML triple-quote syntax
+    if value.contains('\n') {
+        return format!("\"\"\"\n{}\"\"\"", value.replace('\\', "\\\\").replace("\"\"\"", "'\"'\"'\""));
+    }
+    // Default: quote as string
+    format!("\"{}\"", value.replace('\\', "\\\\").replace('"', "\\\""))
+}