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/git_operator.rs

@@ -0,0 +1,67 @@
+use std::process::Command;
+use serde_json::{json, Value};
+use anyhow::{Result, anyhow};
+use super::Tool;
+use super::ToolCtx;
+
+pub struct GitOperator;
+
+impl Tool for GitOperator {
+    fn name(&self) -> &'static str {
+        "git_operator"
+    }
+
+    fn description(&self) -> &'static str {
+        "Execute git operations with catastrophic guard protection"
+    }
+
+    fn parameters(&self) -> Value {
+        json!({
+            "type": "object",
+            "properties": {
+                "operation": {
+                    "type": "string",
+                    "description": "Git subcommand to execute (e.g. 'add', 'commit', 'status')"
+                },
+                "args": {
+                    "type": "array",
+                    "items": {"type": "string"},
+                    "description": "Arguments for the git subcommand"
+                }
+            },
+            "required": ["operation", "args"]
+        })
+    }
+
+    fn run(&self, _ctx: &ToolCtx, args: &Value) -> Result<String> {
+        let operation = args.get("operation")
+            .and_then(|v| v.as_str())
+            .ok_or_else(|| anyhow!("missing required argument: operation"))?
+            .to_string();
+        let arg_list: Vec<String> = args.get("args")
+            .and_then(|v| v.as_array())
+            .map(|arr| {
+                arr.iter()
+                    .filter_map(|v| v.as_str().map(|s| s.to_string()))
+                    .collect()
+            })
+            .ok_or_else(|| anyhow!("missing required argument: args"))?;
+        let full_cmd_str = format!("git {} {}", operation, arg_list.join(" "));
+        let workspace_roots: Vec<&std::path::Path> = _ctx.workspaces.iter().map(|p| p.as_path()).collect();
+        crate::app::catastrophic::CatastrophicGuard::check_all(&full_cmd_str, &workspace_roots)
+            .map_err(|e| anyhow!("catastrophic guard blocked: {}", e))?;
+        let output = Command::new("git")
+            .arg(&operation)
+            .args(&arg_list)
+            .output()
+            .map_err(|e| anyhow!("git {} failed: {}", operation, e))?;
+        let stdout = String::from_utf8_lossy(&output.stdout).to_string();
+        let stderr = String::from_utf8_lossy(&output.stderr).to_string();
+        let combined = if stderr.is_empty() { stdout.trim().to_string() } else { format!("{}\n{}", stdout.trim(), stderr.trim()) };
+        if output.status.success() {
+            Ok(combined)
+        } else {
+            anyhow::bail!("git {} failed (exit {}): {}", operation, output.status.code().unwrap_or(-1), stderr.trim())
+        }
+    }
+}