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/tool/fs/write.rs

@@ -0,0 +1,57 @@
+use std::fs;
+use serde_json::{json, Value};
+use anyhow::{Result, anyhow};
+use super::super::Tool;
+use super::super::ToolCtx;
+use super::super::resolve_path;
+use super::helpers::arg_str;
+
+pub struct Write;
+
+impl Tool for Write {
+    fn name(&self) -> &'static str {
+        "write"
+    }
+
+    fn description(&self) -> &'static str {
+        "Write content to a file, creating parent directories as needed"
+    }
+
+    fn parameters(&self) -> Value {
+        json!({
+            "type": "object",
+            "properties": {
+                "path": {
+                    "type": "string",
+                    "description": "Path to the file to write (relative to workspace root)"
+                },
+                "content": {
+                    "type": "string",
+                    "description": "Content to write to the file"
+                },
+                "reason": {
+                    "type": "string",
+                    "description": "Reason for the change (must be non-empty)"
+                }
+            },
+            "required": ["path", "content", "reason"]
+        })
+    }
+
+    fn run(&self, ctx: &ToolCtx, args: &Value) -> Result<String> {
+        let rel = arg_str(args, "path")?;
+        let content = arg_str(args, "content")?;
+        let reason = arg_str(args, "reason")?;
+        if reason.trim().is_empty() {
+            anyhow::bail!("reason must be a non-empty string");
+        }
+        let path = resolve_path(&ctx.workspaces, &rel)?;
+        if let Some(parent) = path.parent() {
+            fs::create_dir_all(parent)
+                .map_err(|e| anyhow!("failed to create parent directories for '{}': {}", rel, e))?;
+        }
+        fs::write(&path, &content)
+            .map_err(|e| anyhow!("failed to write '{}': {}", rel, e))?;
+        Ok(format!("wrote {} bytes to {}", content.len(), rel))
+    }
+}