feat: add tool framework foundation (types, registry, executor, shell tool, model types, SOUL.md)

- Task 0: SOUL.md + loadSystemPrompt() in daemon
- Task 1: Tool type definitions (Tool, ToolCall, ToolResult, etc.)
- Task 2: ToolRegistry with Anthropic/OpenAI serialization
- Task 3: ToolExecutor with hooks, timeout, truncation
- Task 4: shell.exec builtin tool
- Task 8: Model types updated for tool use (ToolDefinition, ModelToolCall, etc.)
- Task 15: Model index exports for tool types

src/tools/types.test.ts

@@ -0,0 +1,52 @@
+import { describe, it, expect } from 'vitest';
+import type { Tool, ToolCall, ToolResult, ToolUseMessage, ToolResultMessage } from './types.js';
+
+describe('Tool types', () => {
+  it('Tool interface is structurally correct', () => {
+    const tool: Tool = {
+      name: 'test.echo',
+      description: 'Echoes input',
+      inputSchema: {
+        type: 'object',
+        properties: { text: { type: 'string' } },
+        required: ['text'],
+      },
+      execute: async (args) => ({ success: true, output: String((args as { text: string }).text) }),
+    };
+
+    expect(tool.name).toBe('test.echo');
+    expect(tool.inputSchema.type).toBe('object');
+  });
+
+  it('ToolCall has required fields', () => {
+    const call: ToolCall = { id: 'call_1', name: 'test.echo', args: { text: 'hi' } };
+    expect(call.id).toBe('call_1');
+    expect(call.name).toBe('test.echo');
+  });
+
+  it('ToolResult has success and output', () => {
+    const result: ToolResult = { success: true, output: 'hello' };
+    expect(result.success).toBe(true);
+
+    const errResult: ToolResult = { success: false, output: '', error: 'boom' };
+    expect(errResult.error).toBe('boom');
+  });
+
+  it('ToolUseMessage has correct shape', () => {
+    const msg: ToolUseMessage = {
+      role: 'assistant',
+      content: [{ type: 'tool_use', id: 'call_1', name: 'test.echo', input: { text: 'hi' } }],
+    };
+    expect(msg.role).toBe('assistant');
+    expect(msg.content[0].type).toBe('tool_use');
+  });
+
+  it('ToolResultMessage has correct shape', () => {
+    const msg: ToolResultMessage = {
+      role: 'user',
+      content: [{ type: 'tool_result', tool_use_id: 'call_1', content: 'output here' }],
+    };
+    expect(msg.role).toBe('user');
+    expect(msg.content[0].type).toBe('tool_result');
+  });
+});