Add Discord-native hybrid front-end for Jarvis (bot + bridge)

Transform isair/jarvis into a Discord-controlled voice assistant running on
the Ubuntu VNC desktop, keeping the mature ~39k-line Python brain intact.

- bot/ (Node + bun, discord.js): /자비스 slash commands (ephemeral),
  voice channel join + voice receive/playback, pluggable VNC screen broadcast
  (selfbot live / noVNC / screenshot)
- bridge/ (Python, Flask): wraps jarvis STT + run_reply_engine + Piper TTS
  behind a thin localhost HTTP API
- .env.example, scripts/ (start_bridge/start_bot/dev), README rewrite,
  docs/language-comparison.md and docs/vnc-xfce-setup.md

Language decision: hybrid (Python brain + Node/bun Discord layer) because
Discord blocks bot video; native screen broadcast only works via a Node
selfbot library.

tests/tools/builtin/test_local_files.py

@@ -0,0 +1,121 @@
+"""Tests for local files tool."""
+
+import pytest
+from unittest.mock import Mock, patch, mock_open
+import tempfile
+import os
+from pathlib import Path
+
+from src.jarvis.tools.builtin.local_files import LocalFilesTool
+from src.jarvis.tools.base import ToolContext
+from src.jarvis.tools.types import ToolExecutionResult
+
+
+class TestLocalFilesTool:
+    """Test local files tool functionality."""
+
+    def setup_method(self):
+        """Set up test fixtures."""
+        self.tool = LocalFilesTool()
+        self.context = Mock(spec=ToolContext)
+        self.context.user_print = Mock()
+
+    def test_tool_properties(self):
+        """Test tool metadata properties."""
+        assert self.tool.name == "localFiles"
+        assert "file" in self.tool.description.lower()
+        assert self.tool.inputSchema["type"] == "object"
+        assert "operation" in self.tool.inputSchema["required"]
+        assert "path" in self.tool.inputSchema["required"]
+
+    def test_run_no_args(self):
+        """Test local files with no arguments."""
+        result = self.tool.run(None, self.context)
+
+        assert isinstance(result, ToolExecutionResult)
+        assert result.success is False
+        assert "requires a JSON object" in result.reply_text
+
+    def test_run_missing_operation(self):
+        """Test local files with missing operation."""
+        args = {"path": "test.txt"}
+        result = self.tool.run(args, self.context)
+
+        assert isinstance(result, ToolExecutionResult)
+        assert result.success is False
+        assert "requires 'operation'" in result.reply_text
+
+    def test_run_missing_path(self):
+        """Test local files with missing path."""
+        args = {"operation": "read"}
+        result = self.tool.run(args, self.context)
+
+        assert isinstance(result, ToolExecutionResult)
+        assert result.success is False
+        assert "requires 'operation' and 'path'" in result.reply_text
+
+    @patch('pathlib.Path.exists')
+    @patch('pathlib.Path.is_file')
+    @patch('pathlib.Path.read_text')
+    def test_run_read_success(self, mock_read_text, mock_is_file, mock_exists):
+        """Test successful file read."""
+        mock_exists.return_value = True
+        mock_is_file.return_value = True
+        mock_read_text.return_value = "Test content"
+
+        args = {"operation": "read", "path": "~/test.txt"}
+        result = self.tool.run(args, self.context)
+
+        assert isinstance(result, ToolExecutionResult)
+        assert result.success is True
+        assert "Test content" in result.reply_text
+
+    @patch('pathlib.Path.exists')
+    def test_run_read_not_found(self, mock_exists):
+        """Test file read when file doesn't exist."""
+        mock_exists.return_value = False
+
+        args = {"operation": "read", "path": "~/nonexistent.txt"}
+        result = self.tool.run(args, self.context)
+
+        assert isinstance(result, ToolExecutionResult)
+        assert result.success is False
+        assert "not found" in result.reply_text.lower()
+
+    @patch('pathlib.Path.write_text')
+    @patch('pathlib.Path.mkdir')
+    def test_run_write_success(self, mock_mkdir, mock_write_text):
+        """Test successful file write."""
+        args = {"operation": "write", "path": "~/test.txt", "content": "Test content"}
+        result = self.tool.run(args, self.context)
+
+        assert isinstance(result, ToolExecutionResult)
+        assert result.success is True
+        assert "Wrote" in result.reply_text
+
+    def test_run_write_no_content(self):
+        """Test file write without content."""
+        args = {"operation": "write", "path": "~/test.txt"}
+        result = self.tool.run(args, self.context)
+
+        assert isinstance(result, ToolExecutionResult)
+        assert result.success is False
+        assert "requires string 'content'" in result.reply_text
+
+    def test_run_unsafe_path(self):
+        """Test with path outside home directory."""
+        args = {"operation": "read", "path": "/etc/passwd"}
+        result = self.tool.run(args, self.context)
+
+        assert isinstance(result, ToolExecutionResult)
+        assert result.success is False
+        assert "not allowed" in result.reply_text.lower()
+
+    def test_run_unknown_operation(self):
+        """Test with unknown operation."""
+        args = {"operation": "invalid", "path": "~/test.txt"}
+        result = self.tool.run(args, self.context)
+
+        assert isinstance(result, ToolExecutionResult)
+        assert result.success is False
+        assert "Unknown localFiles operation" in result.reply_text