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/store.rs

@@ -0,0 +1,36 @@
+use std::path::PathBuf;
+use serde::{Deserialize, Serialize};
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct Store {
+    pub base_dir: PathBuf,
+    pub scratch_root: PathBuf,
+    pub memory_dir: PathBuf,
+    pub session_images_dir: PathBuf,
+    pub download_dir: PathBuf,
+}
+
+impl Store {
+    pub fn new() -> Self {
+        let base = dirs::data_dir()
+            .unwrap_or_else(|| PathBuf::from(".local/share"))
+            .join("zesdex");
+        let scratch = std::env::temp_dir().join("zesdex-scratch");
+        Store {
+            memory_dir: base.join("memory"),
+            scratch_root: scratch,
+            session_images_dir: base.join("session-images"),
+            download_dir: base.join("downloads"),
+            base_dir: base,
+        }
+    }
+
+    pub fn ensure_dirs(&self) -> std::io::Result<()> {
+        std::fs::create_dir_all(&self.base_dir)?;
+        std::fs::create_dir_all(&self.memory_dir)?;
+        std::fs::create_dir_all(&self.scratch_root)?;
+        std::fs::create_dir_all(&self.session_images_dir)?;
+        std::fs::create_dir_all(&self.download_dir)?;
+        Ok(())
+    }
+}