Implement chat and markdown views, enhance status bar, and add workflow panel

- Added `chat.rs` for rendering chat messages with timestamps and roles.
- Introduced `markdown.rs` for rendering markdown content with styling.
- Created `status.rs` to display the application status bar with session and message counts.
- Developed `workflow.rs` to show the current workflow status, including tool calls and active jobs.
- Established a `theme.rs` for centralized color management across the UI.
- Updated `mod.rs` to include new modules and manage rendering logic.

src/dto/chat/tool.rs

@@ -0,0 +1,34 @@
+use serde::{Deserialize, Serialize};
+use serde_json::Value;
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ToolCall {
+    pub id: String,
+    #[serde(rename = "type")]
+    pub type_: String,
+    pub function: ToolFunction,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ToolFunction {
+    pub name: String,
+    pub arguments: Value,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ToolResult {
+    pub tool_call_id: String,
+    pub output: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub is_error: Option<bool>,
+}
+
+pub fn sanitize_tool_arguments(args: &Value) -> Value {
+    match args {
+        Value::String(s) => {
+            serde_json::from_str(s).unwrap_or_else(|_| args.clone())
+        }
+        obj @ Value::Object(_) => obj.clone(),
+        other => other.clone(),
+    }
+}