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/model/agent_def/global.rs

@@ -0,0 +1,42 @@
+use crate::app::subagent::spawn::AgentDefinition;
+
+pub fn load_global_agents() -> Vec<AgentDefinition> {
+    let store = crate::model::store::Store::new();
+    let agents_dir = store.base_dir.join("agents");
+    if !agents_dir.exists() {
+        return Vec::new();
+    }
+    let mut agents = Vec::new();
+    if let Ok(entries) = std::fs::read_dir(&agents_dir) {
+        for entry in entries.flatten() {
+            let path = entry.path();
+            if path.extension().is_some_and(|e| e == "json") {
+                if let Ok(content) = std::fs::read_to_string(&path) {
+                    if let Ok(def) = serde_json::from_str::<AgentDefinition>(&content) {
+                        agents.push(def);
+                    }
+                }
+            }
+        }
+    }
+    agents
+}
+
+pub fn save_global_agent(def: &AgentDefinition) -> anyhow::Result<()> {
+    let store = crate::model::store::Store::new();
+    let agents_dir = store.base_dir.join("agents");
+    std::fs::create_dir_all(&agents_dir)?;
+    let path = agents_dir.join(format!("{}.json", def.name));
+    let content = serde_json::to_string_pretty(def)?;
+    std::fs::write(path, content)?;
+    Ok(())
+}
+
+pub fn remove_global_agent(name: &str) -> anyhow::Result<()> {
+    let store = crate::model::store::Store::new();
+    let path = store.base_dir.join("agents").join(format!("{}.json", name));
+    if path.exists() {
+        std::fs::remove_file(path)?;
+    }
+    Ok(())
+}