feat: add internal ZCLAW kernel crates to git tracking

crates/zclaw-runtime/src/tool/builtin/file_read.rs

@@ -0,0 +1,55 @@
+//! File read tool
+
+use async_trait::async_trait;
+use serde_json::{json, Value};
+use zclaw_types::{Result, ZclawError};
+
+use crate::tool::{Tool, ToolContext};
+
+pub struct FileReadTool;
+
+impl FileReadTool {
+    pub fn new() -> Self {
+        Self
+    }
+}
+
+#[async_trait]
+impl Tool for FileReadTool {
+    fn name(&self) -> &str {
+        "file_read"
+    }
+
+    fn description(&self) -> &str {
+        "Read the contents of a file from the filesystem"
+    }
+
+    fn input_schema(&self) -> Value {
+        json!({
+            "type": "object",
+            "properties": {
+                "path": {
+                    "type": "string",
+                    "description": "The path to the file to read"
+                }
+            },
+            "required": ["path"]
+        })
+    }
+
+    async fn execute(&self, input: Value, _context: &ToolContext) -> Result<Value> {
+        let path = input["path"].as_str()
+            .ok_or_else(|| ZclawError::InvalidInput("Missing 'path' parameter".into()))?;
+
+        // TODO: Implement actual file reading with path validation
+        Ok(json!({
+            "content": format!("File content placeholder for: {}", path)
+        }))
+    }
+}
+
+impl Default for FileReadTool {
+    fn default() -> Self {
+        Self::new()
+    }
+}